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Marcello Malpighi 1628-1694
By W. G. MacCallum, M. D., Associate Professor of Pathology, The Johns Hopkins University, Baltimore.
- Read at the meeting of the Johns Hopkins Hospital Historical Club, January 16, 1905.
There is in the history of medicine a remarkable contrast between two tj'pes of mind, both of which are represented by great and familiar names. Of these extremes, each of which has nearly always some of the characters of the other, one is made up of those men who, with great personal influence over their fellow-men, use what facts they have at their disposal, or more frequently what convictions are grafted in their minds to construct a theory and from the theory a system of knowledge with an explanation for all difficulties, and a niche even for such as are not yet thought of. Such men were Galen, Paracelsus, Hoffmann, John Brown, Broussais, and many more — men not always without wide knowledge, but who employ rather the deductive method than the inductive. At the other extreme were such as Hippocrates, Vesalius, Harvey, John Hunter, Morgagni, and Malpighi — men who did produce generalizations, but generalizations which were conscientiously based on real facts which they themselves had delved out of nature and which, unlike such systems as Brownianism and the physiological medicine, will last for all time. It is particularly in this character of objective observer, possessed of treasures of fact, before he signed any bond of theory, that Malpighi comes before us to this day as a model. He appeared at an epoch when such giants as Vesalius and Harvey had overthrown the universal confidence in the authority of the ancients — a period when there was suddenly work to do with no appeal to precedent — when the microscope suddenly threw open the enormous field of the minute and invisible, to the searching eye. Letters had fallen to a low ebb — ignorance was vast and overwhelming, and despite the brilliance of the preceding centuries, writers were given over to bombastic ornamentation of their writing, but a few honest and bold spirits turned from authority to nature — exact science arose.
Malpighi was one of the leaders of the movement which tore science from the bonds of tradition and the church, and rendered it independent of the ancient masters who had for so many centuries dominated everything medical.
Marcello Malpighi was born at Crevalcuore, a small town near Bologna, on March 10, 1638. Of his early life nothing is known except that his parents were small landowners who seem to have recognized some ability in their son in sending him to Bologna to study. There he entered the university in 1645 and continued his studies until the death of his parents in 1649, which left to him the care of the large family and of the estate upon which the neighboring family Sbaragli made constant attempts at encroachment. Nevertheless, he resumed his studies next year with the peripatetic philosopher Natali, upon whose advice he took up the study of medicine with Bartolommo Massari and Andrea Mariani. Of these Massari was a diligent anatomist who lost no opportunity of dissecting not only animals but human beings and who formed of his students a small society which met at his house to carry out these dissections. This academy of anatomy, founded in Bologna in 1650, was similar in some respects to the Accademia dei Lincei of Rome, and there being nine students, Massari called it the Coro anatomico in homage to the " coro " of the muses. Among them were Malpighi, Fracassati, Capponi, and Golfieri, and the friendships formed there remained strong through Malpighi's whole life.
At this time the doctrines of Galen and the Arabs still dominated the whole of medicine and teachers merely expounded the works of these authors, sometimes altering them to their great hurt. Malpighi -soon appreciated the fact that Hippocrates had been a more accurate observer of nature than those later writers and devoted his thesis to upholding this view with the result that he greatly irritated his masters who, nevertheless, could not withhold their esteem of so brilliant a student.
In 1654, the year after liis graduation, he married the daughter of his master, Francesca Massari — as Ferrario says, " assai virtuosa donna ma non ebbe figli." This was a very happy imion, although they had no children, and she was his constant companion and support throughout nearly all of his life.
In 1656, when twenty-eight years of age, he was nominated by the Bolognese senate as public lecturer in medicine, three years after his graduation in medicine and philosophy. The liberty to give lectures thus through some animosity withheld from him for a time after his graduation, was granted apparently in connection with Massari's sudden death when he was called to the chair of medicine. In the same year, however, he was requested by Ferdinand II, the grand duke of Tuscany, to come to Pisa, there to give instruction in the science of medicine, and realizing the antagonistic attitude of his own townsmen he accepted the oflier.
There in Pisa he dwelt with one Girolamo Barbato and worked happily in the sunshine of Ferdinand's favor and interest. Borelli, the celebrated mathematician and physicist, became his friend, and the two learned much from one another; Borelli teaching him the philosophy of Galileo, while Malpighi in turn imparted his enthusiasm for biological lore and his knowledge thereof. They two (later with Auber, who discovered the tubular structure of the testis), made many dissections, and the dukes and the princes attended and tempered thus the cares of state. Hence arose the famousAccademia Cimenti, or academy of experiment, which was later transferred to Florence and which, like the Accademia dei Lincei of Kome, numbered some of the most famous men of the times on its rolls.
While at Pisa, Malpighi studied the bullock's heart, macerating and boiling it until he found that the fibers run spirally, and this he at once showed Borelli. Some discussion arose later as to whether the discovery was not Borelli's, but all evidence shows that it was Malpighi who first saw this arrangement. Only in recent years has the completion of this discovery been brought about by one of our own number who showed the continuity of the muscle of the two ventricles in a double roll ending in the papillary muscles.'
Borelli was a man of -marked genius but of irascible temperament, apparently also somewhat unscrupulous about questions of priority, but Malpighi was strongly attracted to him, and until they became estranged years afterward over a question as to the significance of respiration, regarded him almost as a father and constantly sought his counsel. In turn he was one of the few who would listen to Malpighi and approve of his iconoclastic doctrines.
After working thus happily for three years Malpighi, never in robust health and feeling the ill effects of the damp climate, left Pisa and returned to Bologna, having entered into the joys of anatomy and the philosophy of Galileo. While there he had projected a work with the aim of disclosing and remedying the evils of the medicine of that day, but this was not published and seems to have been destroyed in the fire which years later consumed his house.
In 16G0 then he returned to Bologna and found Fracassati and Buonfigluoli there, with whom he resumed his studies. He became interested in the question of respiration and chiefly in the structure of the lung and the coursing of the blood through it, a process which had been shown by Harvey to take place, but which no one had as yet seen nor really comprehended. In two letters to Borelli in 1661 he describes what he has seen, urging his friend to see it too. He determined that the lung is not merely a porous mass into which blood is poured and again sucked out, but showed that the bronchi are continuous with the air vesicles and that the blood is constantly within the blood channels and never poured out into open spaces. One cannot do better than read the translation of these epistles which Sir Michael Foster prints in his interesting lecture on Malpighi, pp. 96-98 :
" For while the heart is still beating two movements contrary in direction are observed in the vessels so that the circulation of the blood is clearly laid bare; and indeed the same may be even more happily recognized in the mesentery and in other larger veins contained in the abdomen. And thus by this impulse the blood is showered down in minute streams through the arteries after the fashion of a flood into the several cells, one or other conspicuous branch passing right through or leaving off there, and the blood thus repeatedly divided loses its red color and carried round in a sinuous
' J. B. MacCallum, Johns Hopkins Hospital Reports, 1900, Vol. IX.
manner is poured out on all sides until it approaches the walls and the angles and the absorbing branches of the veins.
" The power of the eye could not be carried further in the opened living animal ; hence I might have believed that the blood itself escaped into an empty space and was gathered up again by a gaping vessel, and by the structure of the walls. But an objection to this view was afl'orded by the movement of the blood being tortuous and scattered in different directions and by its being united again in a determinate part. My doubt was changed into certainty by the dried lung of the frog which to a very marked extent had preserved the redness of the blood in very minute tracts (which were afterwards found to be vessels). Where, by the help of our more perfect glass, there met the eye no longer scattered points resembling the skin which is called sagrino but vessels joined together in a ring like fashion. And such is the wandering about of these vessels as they proceed on this side from the vein and on the other side from the artery that the vessels no longer maintain a straight direction but there appears a network made up of the continuations of the two vessels. This network not only occupies the whole area but extends to the walls and is attached to the outgoing vessel. Hence it was clear to the senses that the blood flowed always along tortuous vessels and was not poured into spaces, but was always contained within tubules and that its dispersion is due to the multiple winding of the vessels. Nor is it a new thing in nature to join to each other the terminal mouths of vessels since the same obtains in the intestine and other parts.
" All this you will see exceedingly well if yoii examine the turgid lung of a frog with a microscope of a single lens against the horizontal sun."
The significance of this discovery of the capillaries was of course enormous as it cleared up great difficulties not only in the explanation of the physiology of the circulatory system and respiration but especially in that of the glands, for now the function of the gland cells and the ducts could be rationally explained. As to the blood there still reigned obscurity. Malpighi, with the rest, thought the red color generally diffused, and even when several years later in his tract upon the omentum and adipose tissues he describes the corpuscles chiefly in their agglutinated condition as long rolls, he regards them as fat cells and compares them with red coral.'
As to respiration, Malpighi was not especially happy in his surmises, for while he rejected the view of Aristotle that respiration cooled the blood and thus kept it from coagulation — a view accepted by Descartes, Swammerdam, and even Boerhaave — he leaned to the theory of attrition, thinking the motion especially important in favoring fermentation in the blood. This was disproven by the Englishman Hooke, who opened the chest of a dog and while the heart was still beating punctured the lungs everywhere with minute holes. He then caused a blast of air to be blown through them and
'Malpighi observed corpuscles in 1665; Leeuwenhoek described them in 1673; Swammerdam saw them in the frog in 1658, but his publication was in 1737.
thus, although the air leaked out of the holes he had made, the lungs were kept distended with fresh air and motionless and the dog lived for some time. An epistolary polemic between Borelli and Malpighi on the subject was probably the beginning of the rupture between them. Borelli proved that the air entered passively and that it did not entirely leave the lungs at each respiration and he had the luminous idea that the air itself was of use and that it contributed to the functions of the blood — a true divination. Incidentally Malpighi explained the frog's method of respiration which puzzled Borelli, showing that the frog practically swallows air so that respiration would be prevented by holding its mouth open — not, however, by opening its thorax.
Even at this time Malpighi was not exempt from violent attacks from his contemporaries who derided his teachings. One of his former students. Mini, who later became professor at the University of Bologna, attacked him in 1665 in a public denunciation of his teachings, and in 1678 wrote a book against him with the title " Medicus igne non cultro anatomicus," attempting to show the uselessness of anatomical studies in the cure of the sick as compared with a knowledge of the medicines which the fathers had found to be useful. Malpighi grew impatient and replied with some heat to this attack, as it is said, although I can find in his works no printed report of this reply. He must have been much comforted by the support of such men as Bartholin, Willis, and others whose opinions he knew he could respect.
In his earlier years Borelli had lived and taught in Messina and now the news came to him of the death of Pietro Castelli, who had held the chair of medicine. He immediately wrote to recommend his friend Malpighi as the most fitting successor, and the senate accepting his suggestion sent a polite letter to Malpighi requesting him to come there and teach the principles of medicine. This offer he accepted without much hesitation, and in 1663 we find him on his way via Naples to Messina. There in that most beautiful land, surrounded by the teeming Mediterranean he was in a naturalist's paradise. Every kind of animal and plant was at his service. Creatures of the sea were especially abundant and he availed himself of this profusion in marvelous fashion. Thus in the sharks he found the spiral intestinal valve and observed the viviparous habits of some forms. In the swordfish he saw that the optic stalk is composed of a twisted or folded plate, although he did not recognize the significance of this as showing it to be merely a crumpled diverticulum of the brain. He wrote at once to Borelli, who answers in a tone that seems quite modern:
" I was astounded by the drawings of the optic nerve of the swordfish, of which observations you should make great capital, and should easily find traces of this in other larger animals, such as the ox. If it prove to be so I should advise you to compose a treatise upon the subject and have it published."
It was in these fishes, too, that, without knowledge of Willis' book, he first attempted the investigation of the brain, a
task so difficult, on account of the softness of the tissue which he could only overcome by the imperfect method of boiling the brain, that we can only feel surprised that he saw so much as he did. He discerned the cortical cells and their connection with the nerve fibers. Thus he appreciated the relation of the spinal cord and nerves to the brain, but unfortunately he regarded the nerve fibers as tubules {hudellini) which carry a gross secretion from the nerve cells which he thought to have a glandular natuje. This was really a Galenic idea and was soon afterward refuted, but Borelli believed it and quoted it in his book "Do motu animcdium."
During this time Malpighi lived in the house of his interested patron Giacomo RiiiB, Visconti di Francavilla, who watched eagerly all his work and helped him in every way. It was then that he thought of writing a great work on anatomy, reviewing and criticizing all work already done and aU views and theories already expressed in the light of his new discoveries. Haeser, in his history of medicine, regrets that this was never completed, but it seems now that we may feel grateful that when Malpighi consulted with Borelli and Fracassati about this, as was his wont, they wisely dissuaded him from thus examining the work of others, urging him to discover things for himself. Euffi being of the same miad, he returned to his studies of the things themselves and nothing of the book remains except one or two chapters on the circulation and on the lungs which Atti has preserved.
During this time Malpighi's activity must have been enormous. It seems almost impossible that any one could have had time to make so many thorough studies in the intervals which elapsed between his enthusiastic epistles to Borelli and Fracassati and others by which it was his habit to announce each new discovery. His autobiography tells us, however, in the simplest concise way how he was occupied year by year.
" In the meanwhile dwelling in the country not far from the town in the villa of the illustrious Viscount Jacopo Euffi I observed the structure of plants and there in the broken branch of a chestnut saw the air ducts or tracheae which as I have learned exist also in other vegetables. I therefore wrote to ]\Iaster Borelli about it, who answered me thus, 27 April, 1663 :
" ' I thank j'ou for your description of your experience with the air tubes of plants which I have investigated too, but seeing them has not helped me further. Still I believe they are the same tubules that carry water and air and not different ones — as long as experience shall not demonstrate the contrary.' "
Evidently he made but little further study of plants at this time, for he goes on to relate how in his " horse subsecivse " he dissected fishes and other creatures, including various quadrupeds. It was then that he turned his attention to the tongue and its papillae, which were of course well known, but thought to be secretory in nature. This he readily showed to be untrue by allowing the tongue to protrude and dry, when no secretion appeared from the papillse. On the other hand he was able to show their provision of nerve filaments and to deduce from this their gustatory function. Further he recognized the analogy between these and the papillae of the skin, which he studied — one may say discovered. Particularly was he interested by the rete mucosum which he saw first of all and of which we speak in his honor as the Malpighian layer. There, as he pointed out, accumulates the pigment which makes the negro black. The nature of hair, feathers, and the external layers of the skin also fell under his inquiring search, ^though iLeeuwenhoek perhaps described the epidermis more accurately in later years.
In 1665 he was violently attacked by one Michele Liparo, who upheld the ancient Galenic writings against the modern and published a book full of error and slander against Malpighi called " II Trionfo dei Galenici." Malpighi, assuming the name of one of his students, Placidi di Papadopoli, answered him in an epistle " II Apologia dei Moderni," which Fracassati and Borelli wished him to publish, but which by his own will was not printed until the appearance of his posthumous works. This epistle, which begins with a harangue upon the ingratitude of mankind which neglects to read the great book of nature and leans upon authority, goes on to a great length discussing acutely the works of Galen and the interpretations put upon them by those who bow to his dictum.
It must have been during this time, although it is difficult to gather it from his autobiography, that Malpiglii collected together his notes or made the new studies upon the viscera and their minute structure which forms the material for his book " De Viscervm Structvra Exercitatio Anatomica," which was printed in 1666 in Bologna. He writes: "The fourth year of my stay slipping by and the curriculum of lectures being completed I meditated a return to my own country. But it pleased the illustrious senate of Messina to request, on April, 1666, that I should continue yet another four j-ears and with this in view I started to Bologna in the beginning of May with the plan, health, and my domestic affairs permitting, of returning in the autumn. In Naples I met the learned Cornelius and Leonardus and others of that school and talked and consulted with them as long as I was able, to the great recreation of my mind. In Kome it was my fortune to meet for the first time the famous Nicolao Stenone, who was very suave and friendly . . . and many others and at length reached Bologna safely. After a short bodily rest I had printed the material which I had arranged concerning the structure of the viscera."
This tract,, printed separately at least once again by Petrum le Grand in Amsterdam in 1669 and finally in the various editions of his complete works, is one of great interest. It contains essays on the liver, the cerebral cortex, the kidneys, and the spleen, and each of these essays added much to what was known of the anatomy of these organs — indeed they shed the first clear light upon them. Malpighi apologized for writing of the liver after Glisson had written so well, but his contribution, notwithstanding that Glisson had written, is of great importance. He recognized the structure of
the liver as that of a conglomerate gland, composed of hexagonal lobules, the number and structure of which he left to others to discern. He decided, too, that the bile-duct is the ordinary secretory outlet of the liver as in other glands their ducts, and that the bile is actually secreted by the liver and not by the gall-bladder. All these were important advances on the ideas that referred to the liver, chiefiy the function of blood formation.
The essay on the kidneys is a masterpiece. Naturally he knew well the work of Lorenzo Bellini, who, in 1662, described the masses of tubules which make up the cortex, and began with this idea, soon discovering that the tubules are not straight but greatly twisted. He studied the form and general arrangement of the various tissues in the kidneys and we still hear his name in connection with the pyramids, although others must have known them before. He was the first to see the glomeruli, which also bear his name and which he correctly interprets as small tufts of vessels, for he could inject them either from the artery or from the vein. He describes them as hanging from the vessels like apples on a tree. The nature of their connection with the tubules was only explained clearly by Bowman much later, but Malpighi knew that they were connected and attempted to force colored fluids through them into the tubules but with no success. He also injected colored fluids into the ureter and in the living animal tied simultaneously the ureter and veins but without results of which he could be quite sure.
In the spleen he found " glands or vesicles distributed through the whole spleen like bunches of grapes. These have an oval form and are not much larger than the glands of the kidneys. They are, as I always observed, white, and even if the vessels are made turgid with a black injection, they preserve their color. They are soft and friable and one can see no cavity in them." He described also the vessels, parenchyma, trabeculae (which he thought to be muscular), and the capsule and ligated the splenic artery in the dog without apparent effect.
To this there is appended a rather long description of the masses f oimd in the heart after death and entitled " De Pohjpo Cordis." Evidently these were only postmortem clots, and even at the time Kerkringius, in his anatomical observations, contends that it is absurd to think that such masses were present in the living heart. Much more probable is it that they are produced in the dead by the cooling of the blood and the action of acids and other substances. The same mistake has recurred up to our own times and there is still alive a famous Anglo-Indian physician who has described, with vivid regret, the \in timely death of many young soldiers and others from the development of such masses in the heart.
On his return to Bologna, despite his intention of going back .to Messina in the autumn, he was persuaded to stay, and announced his intention to the senate at Messina, who, having already written to hurry him back, then answered accepting, though unwillingly, his resignation, which they took in very good part, wishing him every success and joy.
Thus he writes : " My domestic affairs being arranged and the house in Bologna settled, I went on with my studies with quiet eager mind." He practiced medicine, lectured, made autopsies with the aid of Fracassati and Buonfigluoli and earnestly sought the causes of disease. Besides these occupations he sought the society of friends and especially those of foreign cities, among whom were Sylvius de la Boe, Willis, and Bartholin, and tried by conversing with the celebrated men who passed through Bologna to advance his anatomy and to learn of remedies.
After this he turned his attention to the study of the lymph glands and of the uterus and its appendages. He was the first to describe the Gartner's ducts as Gartner himself stated in his description. This was not all, however, for he saw the uterine glands, studied the placenta which gave him difficulties, saw the Graafian follicles or ova and was the first to describe the corpora lutea. Again, he interests himself in the structure of bones, describing the flat bones especially noting that some bones contain no fat but blood — red marrow — such are the ribs, bones of infants, bones of birds, etc. He saw a cranium among the treasures of the Duke of Modena which was strangely thickened and curved with nodular projections, polished, and white like ivory. This skull he describes in the minutest detail as well as another in which he evidently had to do with a case of osteomyelitis of the jaw with sequestrum formation. Interesting, too, is his description of the aorta of the eminent Cardinal Bonacairsi, which was greatly dilated and lined tliroughout with bony plates and which he thinks might in time have become a continuous bony tube, as has already been observed in others. In another he describes the plaques as like drops of wax. These evidently contained no lime for they burnt readily into a black ash. He has also seen such plaques of bone in the meninges, and in the uterus and in the testicle has found stone-like masses, probably of the same nature. Thus, also, by the inspissation and precipitation of such materials he explains gout-stones. Next he is concerned with teeth and describes the teeth of a great variety of creatures, recognizing the different elements which compose them and describing the enamel as substantia filamentosa. About this time he tells us he became acquainted with Meibomius, Abraham Vilna, Joachim Eisner, and others.
Then, in 16G7, he received a letter from Henry Oldenburg, the secretary of the British Royal Society, expressing their appreciation of his worth and asking him to correspond with them, to send them his works about plants, minerals, insects, particularly about the silk-worm, and to let them know of the works of other eminent writers in Sicily.
"Malpighi answered with what he could of the unedited work of P. Costelli, Maurolicus, Borelli, and others, and set himself to work in 1668 at the cultivation and study of silkworms, " in which I tried to show not onl}' the external mutations but the relations and structure of the viscera. This was a most tedious and laborious task, and fatigued by months of toil I was seized with a fever and an inflammation
of my eyes in the autumn. Still, notwithstanding these difficulties, there was a mental delight in this work — in finding so many and puzzling miracles of nature that I cannot describe them with my pen. My collected observations, with drawings, I sent in the beginning of the year 1669 to the Royal Society."
In this dissertation he described what he saw in watching day by day the silk-worms which he hatched, and dissecting them at various stages. The minuteness and accuracy of his observations are astounding as he goes on to describe the external form, the musculature, the tracheae, the nerves, heart, intestines, etc. Then the metamorphoses and the structures and habits of the adults. The generative organs and egg-laying occupy much of his attention, and all is set forth in the same clear, definite wa}'. Particularly instructive are his references by way of comparison to other insects in which the structures differed slightly. The silk-spinning apparatus he describes and pictures in detail. Especially interesting, too, are his experiments with the tracheae to prove their respira.tory nature. If one apply oil so as to close them the animal dies. That this is not the poisonous property of that particular oil he shows by using other oils or even honey, relating that the creatures after any of these applications die in convulsions, while one may say a paternoster. When they are immersed in water and then allowed to dry they may recover when the water has dried off the orifices of the trachea;. Much of his information on the silk-worm, including his observation that the eggs do not develop unless they have been mixed with the sperm of the male, was published later in his postlnimous works in a letter to Buonfigluoli, etc.
We may here mention his work in connection with other insects, although much of it was not piiblished until many years later. Cattaneo, who has written in an interesting way of Malpighi"s studies of comparative anatomy, has collected together what he has written of insects. It was Malpighi who really discovered the tracheje of insects and also the tubular heart which beats backward through the body, and about which Swammerdam disputed with him. The excretory tubules which hang about the intestine are his very own, too, and bear his name. He regarded them as hepatic in nature, although their real excretory character has since been shown. He drew with care the segmental muscles of the locust and of the pine caterpillar, and in a letter to Bellini in 1689 he actually describes their striation. The nervous cord, with its ganglia and pericesophageal ring, the compound eyes and tactile antennas — all these he described, and he even spent time on ascertaining the nature of the firefly's light, which he thought due to a sulphurous humor, since it gives a humid light which shines even under water. His crowning work on entomology, however, for which the studies of all these other insects were by way of preparation was the description of the silk-worm.
Even before the publication of this work was well under way he bought a villa nearby, at Corticella, and left his chair in Bologna to retire to the country and to study plants. Evidently, however, this did not entirely preclude his indulging in the dissection of all sorts of animals. Everything that fell into his hands was dissected, even the creatures that came as food into his house were sacrificed first to his passion for dissecting, but as there was as yet no rational classification of animals his dissections were more or less isolated, for him at least, and he cannot be regarded as a founder of comparative anatomy except in the sense that he furnished an enormous material for others to analyze and correlate.
In 1669 Steno came to Bologna to visit him, and while he was there Malpighi showed him the muscles of tlie eye of a bird. Unfortunately it was not until after Steno had gone that he saw in the eye of a screech owl which he had opened laterally the inverted image on the retina — " trees, the house. — all inverted and whatever was at the right now came on the left."
Malpighi tells us in his autobiography that now having written of the structure and relations of the organs of animals he turned to the study of the anatomy of plants as being simpler and possibly capable of throwing light upon the other. Accordingly, after two or three years, he had published by the Eoyal Society the " Idea Anat. Plantarum," which was a sort of preliminary communication which expressed all the principles and the essential discoveries whicli he related in detail in his later work, the " Anatomes Plantarum." Curiously enough the " Idea Anatomes Plantarum." with its description of tracheid vessels, etc., was read at the Eoyal Society in 1671, just as Nehemiah Grew's work on the same subject appeared from the press. Grew described tlie tracheid vessels too and thus might claim the priority but he magnanimously resigned that to Malpighi, for he knew that he had made his observation in 1663.
For an idea as to the condition of botany at this time I may draw on Morini's interesting analysis of Malpighi's botanical work. Up to the time of Linnaeus and Tournefort the codex of botanists was the Pinax theatri botanici, the work of forty years of Gaspar Bauhin's life. It was the result of the feverish search of the Germans and Italians for the simples or plants described by Theophrastus, Dioscorides, Aristotle, and Pliny. Then, in the sixteenth century, there arose the botanical gardens; first in Padua, established by Bonafede and da Monte; then in Pisa, Bologna, and in 1577 in Leyden. No rational method of studying plants had been devised, however, until the time of Conrad Gesner, who knew them by their flowers and fruits and in this way gave the basis for the elaborate classification of Linnaeus. C'esalpinus was a botanist, too, as we see by his book (De Plantis, libri xvi, 1583), but they were yet in the beginnings of botany. Analogies, real or supposed, with animals dominated their ideas and the pith was regarded, therefore, as the seat of the vital principle, etc. Malpighi, too, clung for a long time to the idea that a circulation exists in plants comparable to that of animals and searched for valves in the conducting tubules. He had also the idea that there was a widely ramifying vessel taking food to all parts of the plant, and as lie thought (having seen laticiferous and resin-bearing vessels) that he had surely seen this in some plants, hastened to apply the idea to all.
It would be impossible to enter into the details of Malpighi's enormous work which concerns especially phanerogams, but also some pteridophyta, fungi, galls, and parasitic plants. Hooke had seen plant cells and regarded them as merely cavities partitioned off from the general cavity. Malpighi, however, made a distinction between cells and fibers and vessels. With rare perspicacity he saw that all plants are composed of a complex of sacs or vesicles which constitute the fundamental tissues, and these he called otricoli. The generalization of this principle manifests the synthetic power of his mind. He had thus arrived at the modern distinction between parenchyma and prosenchyma, further than which he could scarcely go without a knowledge of protoplasm and the possibilities in the modification of cells.
His recognition of the continuity of leafstalks, branches, stem, and roots, and of the fact that the fioral envelopes and cotyledons are modified leaves brought him very near to the ideas of Wolff and Goethe that all the diverse plant products may be traced from a few single types.
He described minutely with drawings of sections studied microscopically the wood and bark, the medullary rays, the tracheid vessels, scalariform and pitted vessels, sclerenchyma and woody fibers, the medulla, the nature of the annual rings, and so on, but erred in ascribing the origin of the wood fibers to the bast. From watching the growth of many plants he concluded that there was an essential difference between those which grew with one cotyledon only and those which started with two and thus divided as we now divide them, the phanerogamous plants. Not only this but he recognized that there is a fundamental difference in the arrangement of the fibrovascular bundles which corresponds with this division.
Most of his studies were, however, not merely morphological but sought to explain the physiology and laws of development of plants. Up to bis time Cesalpinus had regarded the stamens as a means of draining the ovary and thought that the purified ovary could then produce seeds. Malpighi probably did not actually see the fertilization in the flower, for in studying the embryo he missed the micropyle which Grew had seen. Nevertheless, his work on the development of the ovum into the seed and of the ovary into the fruit and then of the germination of the seed is classical.
He recognized the need of air for plants, and again with his zoophysiological ideas ascribed the function of carrying the air to the tracheids. He found that on submerging them in water covered with a layer of oil they all putrefied and further that they died if he stripped them of leaves. Still he could never find the stomata of leaves and did not recognize the function of the chlorophyll, thinking that the gas exchange was equally carried out by the bark and the pith.
By ringing the stem of a plant he discovered the return current of elaborated materials from the leaves.
The sudden appearance of all this knowledge as to plants at a time when only the wildest speculations had resulted from what little thought had been expended upon them is another evidence of the great originality and independence of Malpighi's mind. His generalizations, too, from his various observations show the touch of genius which is missing in Grew's ponderous work. With the lower plants Malpighi concerned himself less. Busts and smuts attracted his attention and he recognized the sporangia. In the mosses, too, he saw the sporogonia with the peristome and operculum and recognized the spore nature of the dust which one can shake out. Mucor and other moulds he studied too and saw their sporangia if not their spores. Apparently he was the first to describe the tubercles produced by nitrifying bacteria on the roots of leguminous plants, which have roused such interest in late years. Spontaneous generation was generally taught and believed in, but Malpighi took earth from a great depth, put it in a glass vessel which he covered with several layers of silk so that air and water but not the smallest seed could enter. Nothing grew. This seems a remarkable foreshadowing of Pasteur's work and we may imagine with what delight Malpighi would view a modern thermostat with its cultures of bacteria. Of infusoria or any microscopic plants he tells us nothing.
Although we have thus gone on to describe his botanical work at this point, it was not all the work of a year but lasted over several years, and while the " Idea Anatomes Plantarum " was published in 1671, the first part of the "Anatome Plantarum " appeared in 1675, and the second part, also published by the Eoyal Society, not before 1678.
In the meanwhile he was not neglectful of his anatomical interests and in an incredibly short time, amid his other occupations, he watched the hatching of hens' eggs, studying the developing chick at every interval by spreading it out on a glass slide and viewing it with his microscope, until in 1672, there was printed the book " De Formatione Pulli in Ovo," which may perhaps be regarded as the cornerstone of embryology. This paper was sent to the Eoyal Society in February, 1672, but in October of the same year he finished another paper on the same subject, " De Ovo Incubato," which enters much more fully into the details which he observed day by day in subsequent series of chicks. With his new method of floating off the embryo in water and spreading it on a slide, Malpighi was enabled to make many advances over his predecessors, of whom perhaps Harvey ought specially to be mentioned. Evidently, as he himself says, he entered into a very chaos when he undertook the study of this subject. Since he had no other method and seems not even to have dissected his embryos except in the latest stages but to have depended most largely upon their transparency, it is surprising to find how much he actually did see and draw in his figures. Hour by hour he described the changes which he could observe and later day by day. The accuracy and lack of error in his descriptions and drawings is quite marvelous, but it will be
necessary to mention only the chief points. The formation and closure of the medullary groove, the primitive metameres, and the formation of the cerebral vesicles are clearly shown. Then the appearance of the optic vesicles with their stalk, the cleft in the vesicles, and later the lens formation are traced out. The twisting of the body and the appearance and development of the heart from a single bent tube to the perfect arrangement of auricles, ventricle, aortic arches, etc., are described, and the question arises in his mind as to whether the blood or the heart appears first. Later in his posthumous works he abandons this query as not worth labor. The division of the primitive portions of the brain is dwelt on and the modifications of each part described. With the later changes, owing, perhaps to the loss of transparency, he is less fortunate. There is a vague description of the liver, the clear white lungs, and the other organs. I can find no mention of the development of the intestine nor of the generative or renal apparatus. The appearance of the wings and legs and of the protuberances that later produce the feathers, and the feathers themselves are minutely followed. The breaking out of the egg, too, and the constriction and separation of the umbilical vesicles are as clearly described as in any modern book.
During this time he was attacked by many jealous enemies, even among those of his own faculty of Bologna, and so fiercely that Cardinal Pignatelli felt it his duty to interfere and protect him. Among these most prominent was J. Hieronymo Sbaragli, who, in an epistle " De Recentiorum Medicorum Studio, Dissertatio Epistolaris ad Amicum" (Gottingen, Sept., 1687), again, like Minus many years before, ridicules the studies of Malpighi, both anatomical, zootomical, and botanical, on account of their inutility in furthering the cure of disease. Of what use, he says, is the knowledge of the structure of the lung and the streaming of blood through it. Everybody knows that animals breathe but no one knows why, and it may be said even that in this modern seventeenth century, with all this new knowledge at our command, we are not even quite as successful in curing pneumonia as were the fathers of old. Everyone thought, until the work of Wirsung, that the pancreas was just a cushion to support the stomach. What better off are we to know that it has a duct ? Above all of what use to cut up plants and study the hatching of eggs? Can one cure the troubles of women, knowing how the hatching of eggs goes on?
Malpighi replied somewhat querulously in a very long letter in which he republishes Sbaragli's epistle, then taking up clause by clause his objections. What difficulties must have met Malpighi in answering those taunts in those days when he could not persuade his readers of the future of his discoveries, even though he could see it himself, and how completely he has been justified. In our times the situation is difl'erent. Great good has been shown to come from some of these seemingly irrelevant discoveries and now everyone is willing to believe in such apparent side-paths of research and to wait hopefully for the practical result. Still Malpighi was not without a response. Precisely in the case of the pancreas he recounts the knowledge of the day, saying that the secretion poured out from that duct, mixing with the bile and the chyle " provokes a peaceful fermentation," and that if it be prevented from so flowing or its character destroyed the person will waste away in an cachexia and that here at once we have a new knowledge of the cause of a disease. Of the hatching of the egg he immediately points to the hj'datidiform mole and the abortions which are examples of the results of disturbance in this development. It was the fault of the times that such a ridicule could come to him — not the fault of his honest work.
The quarrel with the Sbaraglis, whicli lasted tliroughout Malpighi's life time and which concerned at first their adjoining estates and afterward, as we have seen, the doctrines of Malpighi, was marked by shameless acts of violence on the part of the Sbaraglis and even went so far that one of Sbaragli family was killed in an encounter with Malpighi's brother Bartolommeo.
It was about this tiriie that he thought of collecting all his works and publishing a corrected edition. Then it was, too, that he wrote his autobiography which appears in his posthumous works and from which most of the details of his life have been learned. In this journal, which was by no means so detailed as his diary which he kept regularly from 1660 to 1694, he relates the main events of his life and discusses his works, criticising them and giving in full the criticisms of his contemporaries and his answers. He freely points out the weaknesses of his works and as freely acknowledges the good work of others.
In 1680 Malpighi sent his porti-ait, painted by Tobar in oil, to the Royal Society with a complimentary letter. They put it up carefully in a frame and Malpighi wrote to thank them for their care.
In 1683 he sent them a letter on the structure of the uterus, on a malformed kidney, on horns, glands, etc. The -epidermal structures had long interested him and he devotes himself for a time to the study of hairs, feathers, and horns, studying the latter from their embryonic state in the bull and even describing a curious case in which a horn developed in the neck of one of these animals.
In the next year a fire broke out in his house, the villa at Corticella, and destroyed it completely together with many of his cherished possessions. A letter to Eedi, which is published in his works (Opere de Fr. Eedi, 1811), gives us an idea of the desolation into which he was plunged by this disaster : " I live, if it can be called life, in idleness, without other aim than to distract my grief. A chance fire in my house in the last month has burned what little I had, my notes in manuscript, the microscopes and lenses — only one was saved and a short time afterward this was stolen .from me with a little money. I must recognize in this the voice of heaven, the more that to mv old ills there are added articular pains which fetter me close so that nothing remains to me but to study and enjoy as best I can the work of others."
The correspondence with the Royal Society was interrupted from this time, 1684 until 1688, when they sent him a let
ter saying that they held him in high respect and asking for his most recent discoveries. He responded with the " Epistola de Glandularum Conglobatarum Structura," in which ho describes the distribution of these masses in various animals, their consistence, form, and color and their relation to the blood-vessels. He recognized, too, that they formed a portion of the lymphatic system and were directly intercalated in the lymph channels, although, as he tells us, these channels are so delicate and friable that it is practically impossible to dissect them out or even to obtain a very satisfactory injection. He names them lymphatic glands and goes on to describe some pathological changes, such as tuberculosis of the gland which can be recognized from his description, but which he also designates as tuberculosis, describing the relation of this lesion to the analogous condition in the lung.
Malpighi was now sixty years old, and after this there was hardly anything more of importance from his pen. It is true that he wrote, as we see in his posthumous works, notes upon flukes and taenias which he found in various animals, but they are not particularly happy descriptions. In the tfenias he saw the suckers which he regarded as eyes with closed lids and the booklets which he thought the teeth about the mouth ; he could see no intestine, but the uterus with its eggs he saw, although he did not interpret it.
In 1691 he was asked by his old friend Cardinal Pignatelli, now Pope Innocent XII, to come to Rome to be his archiatcr or personal physician. Malpighi hesitated, partly on account of his ill health, partly because he had no taste for the position, but the pope would take no denial, and he set out for Rome. His autobiography tells us nothing of the period which followed this. He left Bologna, though, amid the general regret of the people who were loud in their expressions of affection and admiration, and reached Rome where he was received with profound respect. In 1693 Waller, the secretary of the Royal Society, wrote to congratulate him on his new position, and Malpighi answered, later writing to describe the earthquakes in Sicily. In Julj^, 1694, he had an apopletic attack, the nature of which he recognized. It filled him with gloomy forebodings of his approaching end and he hurried to put in order his worldly affairs and to collect his notes — the notes which later appeared in his posthumous works. In November another attack came ypon him as he had foreseen. On his deathbed he instructed de Fabri to send the rest of his manuscript to the Royal Society, and this wish was carried out by Buonfigluoli, his lifelong friend. They were properly printed by Churchill in 1696, and twenty copies were sent to Buonfigluoli. Malpighi died on November 29, 1694, in the Palazzo Quirinale. To Baglivi fell the dolorous task of performing an autopsy and embalming the body, which was afterward transported to Bologna and buried in the Church of San Giorgio. Baglivi's report is concise and I may repeat it here :
"Marcellus Malpighius ann. aetat 66. circiter, temperamenti ad siccum vergentis, mediocri corporis habitu, & mediocri pariter statura praeditus; cum per decursum plurium virilitatis suae annorum obnoxius fuisset vomitibus & seeessi
bvis biliosis, & post horum suppressionem vomitibiis acid is, palpitationibus cordis, calculis renum & vesicae, urinis cruentis, & interdum affectionibus podagricis levioribiis : demum exaeerbatis his omnibus post illius adventiim Eomam, praesertim palpitatione cordis, calculi renum, & sudoribus quibusdam vespertinis, iisque mordaeissimis, correptus fuit apoplexia 25. Julii ann. 1694, hora circiter meridiana, praecedentibus curis, & animi passionibus, &c. Apoplexiae accessit paralysis totius dextri lateris corporis, tortura oris & ocv.li
pariter dextri, &c Die 29. mensis Novembris ejusdem
anni denuo correptus fuit apoplexia post injectum consuetum clysterem hora matutina. Xovam banc apoplexiae invasionem praecesserunt gravissimae vertigines cum exacerbatione calculosa vesicae fere per integrum octiduum; inappertentiae, & reliqua s3'mptomata antedicta graviora erant: sed vehementior his omnibus fuit novae apoplexiae insultus; nam irritis quibuslibet remediis post quatuor ad invasione boras, migravit ad superos.
" Sectio Cadaveeis.
" Secto cadavere observavi, sinistram pulmonum partem aliquatenus flaccescentum lividam, praesertim inposteriori illius parte, qua dorso adhaeret. Cor erat mole sua auctum, & praecipue parietes sinistri ventrieuli, qui duorum digitorum latitudinem aequabant. Bills in vesica fellea valde nigricabat : Een sinister in naturali statu erat, dexter contra quasi medietate minor sinistro, ejusque pelvis adeo dilatata, ut duo digiti commode intrudi possent: ob banc pelvis dilatationem succedebat, forsan ut calculi in renibus geniti statim in vesicam descenderent, & e vesica foras prosilirent, ut pluries mihi testatus est, dum esset in vivis Vir optimus. In vesica urinaria parvus calculus aderat, qui quatuor diebus ante invasionem ultimi accidentis apoplectici inibi descenderat, & deseendendo vertigines illas ultimas exacerbavit. Reliqua viscera naturalia optime se habebant.
"Aperto capite, in eavitate dextri ventrieuli cerebri duas libras circiter sanguinis nigri & grumosi extravasatas invenimus, quae sanguinis evasatio apoplexiae causa fuit & mortis. In sinistro ventriculo residebat aqua sub flava ad pondus sesquiunciae, eique intermixtae erant minimae arenulae exigua quantitate. Vasa cerebri sanguifera erant undequaque varicosa. TJniversa dura mater fortiter ac praeternaturaliter adhaerebat cranio."
Even more detailed and interesting is the account of the personal history of Malpighi which we find in the note of J. Marie Laneisi, which is printed in the Proceedings of the Royal Society and which I may repeat in full :
"The incomparable Malpighi who industriously applied himself to very serious Studies was of a good Habit of Body and had seen 66 Years, but he had frequent Sicknesses; Sharp Vomitings did torment him for 20 years. He was troubled with the gravel, a Hosmorrhagia in the Kidneys, a Rheumatism fluxions which with the troublesome consequences augmented his Infirmities. Scarce had these Evils given him some Respite when a cruel palpitation of the
Heart with an unequal Pulse came upon him. Moreover 4 years before his death a sharp and biting sweait failed not all the summer to trouble him every night. Pope Innocent XII having called him to Rome to make him his chief Physician he began the first year to lose his fresh Color. In the second he voided many Stones without much pain and in the third which was the last of his life he found himself oppressed during the Winter with a difficulty of breathing.
" His health being thus insensibly undermined and a bilious looseness returning ever and anon he was at length seized with a Vertigo and loss of speech and Contorsion of the mouth (Spasmus Cynicus) and a palsy of half the right side, and tho there was appearance that he was out of danger by Bleedings, Purges, Diuretics, Antapoplectic medicines, yet one might see by his melancholy countenance but especially his want of memory that there was lodged in his Brain some melancholy Humour. Therefore perceiving his end drawing near, he signed with his Hand 3 days before his death his Posthumous works which he had ordered to be delivered to his Colleagues of the Royal Society at London. Then having confessed himself with gi-eat humility he attended generously with faith in God the death which appeared to him certain and not far off and on the 28th of November, 1694, a terrible apoplexy finished in the space of four hours this so precious life.
" The learned man foresaw that he should end his days by an Apoplexy and therefore forbad his friends to open his body until 30 hours after his death for he knew well enough that some who seemed dead on a sudden have revived some hours after. When he was opened we found the bladder of Gall abounded with a black Gall. The left kidney had nothing amiss but the right was twice as little and had its Pelvis twice as big which discovered the cause of the easy descent of the stones. We found in the bladder a little Stone that seemed to have fallen into it a few days before. The Lungs appeared withered with some mark of corruption on the back side. The Heart was bigger than ordinary, and the sides of the left ventricle felt harder and thicker in some places than in others. Yet there was no polypus foimd in it.
" The right ventricle of the Brain contained almost two ounces of extravasated blood and the left ventricle was swelled with a thick and 3-ellow sort of Phlegm which weighed more than an ounce. Moreover the dura mater stuck closer to the skull than is usual. This proves that the conglobated glands in the whole body had thrown into the mass of the blood an acid lymph, and that the conglomerated glands of the hypochondria — especially those of the liver had thrown into it a melancholy humor and that these two sorts of humors being carried into the vessels of the Brain had disposed the blood to coagulate there, and that having there corroded and broken the tunicles which served for a stop to them they had run into the cavities where they caused death without a remedy.
" J. Marie Lancisi."
It is difficult for any one person to form a just estimate of Malpighi's worth because his activities, lilce those of Virchow, ramify into so many widely different researches that there are few even at this day who can appreciate their details. Anatomy both human and comparative, physiology, general medicine, embryology, and botany — these, together with a minute study of entomology in both its anatomical and physiological aspect, were the things that occupied his mind. We cannot but regard his anatomical discoveries as of the first importance, and chief among these the capillary circulation and the explanation of the structure of the various viscera. His other numerous discoveries form a mass of new facts, such as it has been the fortune of scarce any anatomist to produce. Together, with his embryological studies, they form the basis for the great principle of the fundamental similarity among animals and the repetition of the principles of biology in the ontogenesis of various creatures.
In his botanical work he has always been compared with Grew, whose similar work on the same subject appeared at the same time. Sachs in his " Geschichte der Botanik," contrasts the two, pointing out that while Grew spent his whole life on phytotomy and amassed a quantity of facts, theorizing only too profusely on them, Malpighi tells us in a genial conversational style of his observations without undue surmises or philosophy.
After all is considered the most enduring things in Malpighi's books are his perfect honesty, his extraordinary keenness and good sense in the interpretation of what he saw and, his ingenious objective methods of observation. What he saw could not have failed of being seen very soon by others, but we are filled with wonder that quite alone, with his " quiet eager mind," he could have encompassed all, steadily searching out one thing after another throughout his forty years of restless activity.
