Prize Essay on the Corpus Luteum (1851) 3
Part 3 Observations on Animals
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Dalton JC. Prize essay on the corpus luteum of menstruation and pregnancy. (1851) Philadelphia: T.K. and P.G. Collins.
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| Corpus Luteum 1851: Part 1 - Corpus Luteum of Menstruation | Part 2 - Corpus Luteum of Pregnancy | Part 3 - Observations on Animals | Plates |
It so frequently happens that a great deal of light is thrown upon obscure portions of human physiology by parallel observations on the lower animals, that it seems hardly excusable, in a question involving much difficulty, to neglect so obvious a source of additional information. Consequently, it has been thought best, in the present instance, to extend our inquiries concerning the corpus luteum into other classes of the mammalia. Among the best subjects for that purpose are the cow and the sheep; not only on account of the comparative ease with which specimens can be obtained from healthy subjects slaughtered for the market, but also from the circumstance that, in a large proportion of these cases, the animal is found to be more or less advanced in the early part of pregnancy. The writer having also been favoured by chance in obtaining one or two specimens from the cow at a much later period of gestation, it was thought too good an opportunity for investigation to be lost ; and he has been enabled, accordingly, to obtain a series of corpora lutea in their different stages, which, though not quite complete, will not, it is thought, be found entirely without value.
The frequency with which the periods of heat recur in these animals also affords an opportunity of examining an abundance of corpora lutea unconnected with pregnancy. Indeed, among all the cases in -which these observations Avere made during the months of December and January, I never failed to discover these bodies in the ovary except in a few instances, in which the animals were very young, and ovulation had evidently not yet been fully established.
The exact periods at which the venereal excitement returns is not very easily ascertained. The butchers and drovers vary a little in their account of it; some stating the interval, in the cow, to be about six weeks ; others about four weeks. In the sheep, during cool weather, it is said to be even less than that. I am informed, however, by Col. Jacques, of Medford, who has been for many years an extensive breeder, that the cow, if kept from the bull, is at heat, for twenty-four hours, as often as once in two or three weeks throughout the year. With regard to the sheep, he is not so positive, but thinks that the periods return about as frequently as in the cow.
For our present purposes, indeed, it is not necessary to ascertain these intervals precisely. It is sufficient to know that they are very short, in order to comprehend how rapidly the corpora lutea become atrophied and disappear, unless their ordinary course of development is modified by the occurrence of pregnancy.
Observation XIX
A Graafian vesicle recently ruptured — Corpus luteum of the preceding ovulation retrograde — Eight others quite obsolete.
I obtained the uterus and ovaries of a healthy cow, slaughtered for the market, December 12th, 1850. The uterus was empty, and there was nothing of note discovered in the tubes.
One of the ovaries was of the usual size, and without any remarkable appearance externally on a superficial examination. There were quite a number of Graafian vesicles to be seen, not prominent, but easily detected at various spots immediately underneath the peritoneum. On close examination; an opening was discovered on one of the lateral surfaces of the ovary leading into the interior of a Graafian vesicle. The walls of the vesicle had collapsed at the surface of the ovary, and the edges of the aperture having consequently been brought in contact, the opening was not at first noticeable. On distending the vesicle, however, with a blowpipe, it became very distinct, of an oval form, with thin sharp edges, and a little over one-sixteenth of an inch in length. (Fig. 17.) There was no ragged or lacerated appearance, nor any unusual vascularity about the rupture, nor any effusion of blood. The vesicle, cut open, was quite empty, and its walls smooth, shining, and vascular as usual. It was of a very moderate size — not over a quarter of an inch in diameter — while very near it was another vesicle, unruptured, half an inch in diameter. Except for the opening in its walls, the ruptured vesicle could not have been distinguished from any other.
The opposite ovary had on its free edge a roundish yellow spot where the fibrous tunic was wanting. There was no prominence at this spot, but immediately underneath was a corpus luteum of considerable size, but still evidently retrograde. This body was solid, with a nearly circular section, five-eighths to three-quarters of an inch in diameter, and showed very plainly the deep foldings of the yellow walls, with a white cicatrix in the centre, from which a wavy line proceeded to the exterior of the ovary indicating the situation of the rupture. (Fig. 18.) The substance of the wall was softish, of a bright stone-yellow colour. Its exterior presented a very thin investing membrane, to which it was so closely adherent that it could not be separated without tearing open the convolutions, and which had, indeed, the appearance of a mere membranous surface. External to this were numerous and dense laminae of cellular tissue.
Fig. 17. Ovary of an unimpregnated cow ; showing a reoently-rupf iired Graafian ves^icle, as it appeared distended by the blowpipe.
Fig. 18. Corpus luteum of the unimprenmated cow at the time of the rupture of the succeeding- vesicle.
There were also in the same ovary five superficial obsolete-looking bodies, corresponding to coloured spots on the surface. The largest was three-sixteenths of an inch deep, and of a dingy-yellow colour, the others successively diminishing in size, and of a brickred tinge. They were all of a close, reticulated-looking texture, ■ and without any distinct investing membrane, but immediately connected with the ovarian tissue, so that they could not be enucleated.
The larger still showed a whitish or transparent central cicatrix, but the smaller presented no trace of it.
The other ovary also contained three similar bodies.
There were many Graafian vesicles to be seen, of moderate size and slightly prominent on the surface.
Observation XX
Ruptured Graafian vesicle in process of transformation into a corpus luteum.
A cow was slaughtered December 12th, 1850, of which the uterus was empty.
One of the ovaries, an inch and a half in length, showed at one extremity a circular spot, a quarter of an inch in diameter, where the fibrous tunic was wanting. There was at this spot a slight eminence, of a very pale yellowish tinge, hardly differing from that of the rest of the ovary except just at its summit, where it was deeply stained of a blood-red colour, and about its circumference, where there was a bright circle of vascularity. The peritoneum extended completely over its surface. (Plate III. Fig. 1, b.)
On the other extremity of the organ was the yellow protrusion of a retrograde corpus luteum. This protrusion was of a light yellow colour and of an oval form, measuring three-eighths of an inch in its long diameter. The corpus luteum underneath could still be felt through theovarian parietes. (Plate III. Fig. 1, a.)
On making a longitudinal incision, so directed as to pass through the centre of each of these spots, a body was found, situated beneath the first, three-eighths of an inch deep, and of a yellowish-white colour, like fibrin, hardly differing in tint from the remainder of the ovarian tissue. It contained a cavity, the proportionate size of which is represented in Plate III. Fig. 2, b. This cavity communicated by a wide passage with the exterior of the ovary, where, however, it was closed by peritoneum, which had been reproduced over the summit of the prominence. The cavity contained a little reddish serum and a plug of fibrin, lying loose towards its deeper part, but •adherent to the peritoneum where it extended over the top of the passage. There was no lining membrane to the cavity^ but the plug was in immediate contact with the foldings of the wall which projected into tlie interior. These convolutions could be readily separated and unfolded from the inside. Externally the wall was adherent to a single thin vascular membrane, with which it could be removed entire ; and beyond this were the usual irregular layers of cellular tissue. The corpus luteum at the other extremity of the ovary was a little over half an inch in depth, and of a bright yellow colour, slightly tinged with orange. (Plate III. Fig. 2, a.) It was solid, and of rather a firm consistency; its central cicatrix somewhat indistinct, but its substance everywhere intersected by streaks of dense cellular tissue, which appeared to have encroached upon the . yellow matter. The substance of this corpus luteum had the same relation to the external parts as in other cases ; only the adhesion between its proper membrane and the outer layers of cellular tissue was closer than in the earlier specimens, so that it could not readily be enucleated. The outer layers were also particularly thick and dense. The same ovary had on its surface two small brick-red spots, corresponding to obsolete corpora lutea of the same colour: the largest an eighth of an inch deep. The other ovary contained six similar bodies, the largest, which was yellowish in colour, one-quarter of an inch in diameter; the others were red, and diminished successively in size. Both ovaries showed several slightly prominent Graafian vesicles, the largest three-eighths of an inch in diameter.
Observation XXI
Corpus luteum of the cow at Its maximum of development — Eight other obsolete.
Uterus and ovaries of a cow slaughtered December 11th, 1850. The uterus was empty.
One of the ovaries measured one inch and three-eighths in length. On its free edge was a large yellowish eminence, of a rather firm consistency, the summit of which was destitute of fibrous covering, and had the aspect of a protruding fungous growth, invested only by peritoneum, which allowed the yellow colour of the corpus luteum to show through very distinctly. (Plate III. Fig. 3.) This fungous protuberance was of an oval shape, and nearly three-fourths of an inch in its long diameter. About its base, where the fibrous tunic of the ovary terminated, vras a somewhat distinct constriction. Its centre showed a distinct, radiated, white line. The sides of the eminence towards its summit were covered with large red and purple vessels.
On a longitudinal section, the corpus luteum was seen to be of very large size ; nearly one inch in its long diameter. It was solid, with a distinct, central, whitish, radiated cicatrix, and strongly marked convolutions. Its colour was yellowish, with an orange tint. There were some minute red vessels, ramifying in the interstices of the convolutions. (Plate III. Fig. 4.)
This corpus luteum had the same relations to the investing membranes as in other cases, i. e., it was covered externally by a single, thin, transparent, vascular tunic, to which it was adherent, and outside of this membrane were several irregular layers of cellular tissue, forming a nidus or receptacle for the body. The first membrane penetrated all the sinuosities of the yellow matter, as the pia mater penetrates between the convolutions of the brain, while the cellular layers passed directly across them, in the manner of the arachnoid.
The ovary contained also Graafian vesicles of moderate size, varying from three-sixteenths of an inch in diameter downward, and four coloured spots on its surface, marking the situations of obsolete corpora lutea. The largest of these latter bodies was a quarter of an inch in depth, and of a yellowish colour. The others diminished successively in size, and were of a brick-red tinge. They were similar in texture to those already described in previous observations.
The opposite ovary contained four obsolete reddish-yellow bodies superficially situated, and many Graafian vesicles, some of which were moderately prominent; the largest half an inch in diameter. Nothing else remarkable.
Observation XXII
Corpus luteum of the cow, beginning to retrograde — Graafian vesicle in the opposite ovary very prominent, and near the time of rupture — Eight obsolete corpora lutea.
Uterus and ovaries of a cow slaughtered Dec. 5th, 1850. The uterus contained several drachms of a clear, serous-looking fluid, but no foetus nor any distinguishable ovum.
One of the ovaries was one inch and three-eighths in length.
It was, for the most part, pale externally. Its surface showed some slight sinuosities, and three small yellowish-red spots, the longest measuring nearly one-eighth of an inch. There were also several translucent Graafian vesicles, situated immediately beneath the albugineous tunic, but none so prominent as to distend the peritoneal coat. On one of its lateral surfaces was a bulky, nipple-shaped protuberance, of a yellowish colour, and firm, resisting feel. It was covered with a few small red vessels, but the vascularity was much less pronounced than in the preceding case. In other respects, it resembled that last described, except for being considerably smaller. On the sides of the protuberance the albugineous tunic was much thinned and nearly transparent, and on the summit it was entirely wanting for a space of rather more than three-eighths of an inch diameter, where the surface was very yellow, and had a soft, velvety appearance. The middle of the summit showed an indistinct, whitish, radiated line, with small red vessels ramifying from it as a centre. (Plate III. Fig. 5.)
This protuberance was formed by the projection of a corpus luteum, which, on a section, was seen to be of an ovoid shape, three-quarters of an inch in its longest diameter, and of a stone-yellow colour. It was solid, with a central linear cicatrix, and numerous convolutions visible throughout its substance. It showed no vessels except a few occasionally penetrating the interstices between the convolutions. There were none whatever in the substance of the yellow matter. As in the cases already described, the yellow matter was closely adherent to a thin, transparent, vascular investing membrane, and there was no distinct membrane external to this; only irregular laminae of cellular tissue. (Plate IV. Fig. 1.)
On cutting through the three reddish spots on the surface of the ovary, there was found immediately beneath each a flattened solid body, of a nearly brick-red colour, and appearing to the naked eye composed of areolar tissue. The two larger were nearly three-sixteenths of an inch in diameter ; the third was somewhat smaller. A central cicatrix was easily distinguishable. They were tough, and closely adherent to the adjacent ovarian tissue. They had no distinct investing membrane, and could not be enucleated from the ovary.
The opposite ovary contained numerous Graafian vesicles in active development. One of them was exceedingly large and prominent, nearly three-quarters of an inch in diameter, and protruding strongly from the surface of the ovary. The tunics of the ovary were very thin over the whole prominence, and at its summit seemed reduced merely to a layer of peritoneum. A few red vessels ramified over
the surface of the vesicle, which was filled with a transparent, colourless, albuminous fluid, holding in suspension minute whitish flakes and shreds. The lining membrane of the vesicle was smooth, transparent, and vascular, not at all folded or discoloured; having, indeed, every way its usual appearance.
The ovary had besides upon its surface five small yellowish or red spots, each of which corresponded to a flattened reddish body, situated immediately beneath, precisely like those
Ovary of an iin impregnated cow; showing a prominent Graafian vesicle. m the Other OVary.
Observation XXIII
Corpus luteum of a cow about three and a half months pregnant.
This cow was slaughtered Dec. 7th, 1850. One of the uterine cornua contained a foetus weighing a pound and a half. The eyelids of the foetus were agglutinated. The skin was perfectly naked, and covered with a fine vascular network.
The ovary corresponding to that horn of the uterus which contained the foetus, presented on one of its lateral surfaces a yellowish projection, similar to that described in Observation XXII., only not quite so prominent. Its summit had the same softish, velvety appearance, With a central radiated white line. The substance of the corpus luteum, however, felt through the ovarian walls, was not so firm and resisting as in the preceding case, but softish, and even gave to the fingers an indistinct sense of fluctuation. On making a longitudinal incision, the corpus luteum was found to be very large, measuring five-eighths of an inch in depth. It was solid like the. others, and had a very evident white, radiated, central cicatrix. Its substance was of a rich, soft, pulpy consistency, and its colour was a deep orange yellow, very distinguishable from the pale stone-yellow of the preceding observation. Its relations to the investing membrane, &c. were the same as in previous cases. (Plate IV., Fig. 2.)
Beside this body, the ovaries contained five obsolete bodies of a brick-red colour and three of a dingy yellow, the situation of which was marked by similar spots on the surface. The structure of these obsolete bodies was the same as has been already described in previous cases.
There were no projecting Graafian vesicles in either ovary, but an abundance of them, of moderate size, buried beneath the albugineous tunic.
Observation XXIV
Corpora lutea of cows, from five to six and a half months pregnant.
On the 20th of Dec. 1850, I obtained the uterine organs of three cows which had been slaughtered Within a day or two.
The first uterus contained a well formed foetus that weighed a little over five pounds. The ovary corresponding to the uterine horn which enclosed the foetus, contained a corpus luteum, ovoid in shape, of a softish, rich, pulpy consistency, and a deep orangeyellow colour, and measuring seven-eighths of an inch in length, by five-eighths in depth. Its section showed plenty of vessels in the interstices of the convolutions. There was also some vascularity externally, on the sides of the tumour.
The ovaries contained also three obsolete corpora lutea of a brickred colour, the largest of which was one-eighth of an inch in depth.
There were also several Graafian vesicles, slightly prominent, the largest a little over a quarter of an inch in diameter.
The second uterus contained a foetus weighing a little less than ten pounds. The ovary, corresponding to the pregnant horn of the uteru", contained a corpus luteum of an ovoid shape, rather over seven-eighths of an inch in length by three-quarters in depth. It was soft and pulpy, and of a very strong orange-yellow colour. There was no vascularity externally.
The ovary contained also three obsolete bodies, very small and of a red colour, and several Graafian vesicles, one of which was slightly prominent but the others nearly or quite concealed beneath the ovarian integuments.
The other ovary was in an extremely inactive condition, though natural in structure. It presented absolutely no obsolete corpora lutea, and no Graafian vesicles at all prominent.
The third uterus contained a foetus weighing fifteen pounds. The ovary corresponding to the pregnant horn presented a soft and pulpy corpus luteum, measuring one inch in its long, and fifteen-sixteenths of an inch in its short diameter, and of a deep orange-yellow colour. There was no vascularity externally. The ovaries contained, beside, only two obsolete red bodies. There were no prominent Graafian vesicles, and only a few small ones superficially situated.
Observation XXV
Corpus luteum of a cow about six and a half months pregnant.
The cow was killed on the 12th of December, 1850. The uterus contained a foetus weighing sixteen pounds. The eyelids were still agglutinated, but could be separated by gentle traction. Hair was just beginning to show itself on the forehead, but the remainder of the skin was quite naked.
The ovary corresponding to the pregnant horn of the uterus was one inch and five-eighths in length. One end of it was occupied by a yellowish tumour, on the summit of which was a nearly circular spot where the fibrous tunic was wanting, and the yellow colour consequently more distinct. The tumour was of a rounded form and a softish consistency. Its sides were pretty abundantly covered with red and purple vessels.
The section of this corpus luteum was solid, but its central cicatrix was still easily recognizable. The body was of an ovoid shape and measured one inch and one-eighth in its long diameter. Its substance was of a strong orange colour, and presented in a high degree the soft, rich, pulpy aspect, already observed as belonging to the corpora lutea of pregnant cows. The structure of the body was the same as in the preceding cases.
Fig. 20. Corpus luteum of a cow about six and a half months pregnant.
The ovaries contained also one obsolete corpus luteum of a red colour, and five others of a yellowish tinge ; but the latter were all exceedingly small and very faint. Nearly all the Graafian vesicles were situated entirely underneath the albugineous tunic. None observed prominent.
Observation XXVI
Corpus luteum of a cow eight months pregnant.
A cow, belonging to Mr. Potter, of Cambridge, was found to be sick on the morning of Friday, November 29th, 1850. She had been covered by the bull in the early part of April in the same year, and had been with young ever since. The animal appeared dull, seemed to sufi'er from pain internally, and had some coolness of the ears and horns. She rapidly grew worse, and on Sunday there was much vomiting and swelling of the abdomen. She died on the afternoon of Sunday, having a short time before expelled a calf that weighed thirty-three pounds.
At the examination of the body, on the same day, there was found very extensive peritonitis which appeared to radiate from a spot on the surface of the "paunch," or first stomach, corresponding in situation to a similar spot of ecchymosis in the thickness of the abdominal parietes. The animal had apparently received a blow in the abdo men which gave rise to peritoneal inflammation.
The left horn of the uterus, moderately contracted, still contained the greater part of the membranes belonging to the foetus which had been expelled. The right horn contained a second foetus, dead, but quite fresh looking, and well developed. Its weight was forty-two and a half pounds.
The left ovary was one and a half inches in length. It had no well marked cicatrices on its surface, but showed at one extremity a slightly prominent Graafian vesicle, three-sixteenths of an inch in diameter. There were also numerous others, much smaller, on the lateral surfaces of the organ. On the free edge of the ovary there was an abrupt prominence, a quarter of an incli in height and threeeighths in length, of a faint orange-yellow colour. The peritoneum was continuous over the whole of the tumour, and on its summit there was a faint, whitish, radiated cicatrix. The base of the tumour was somewhat constricted, and just at the line of constriction, there existed some purplish vascularity.
On making a longitudinal section of the ovary, through the remains of the cicatrix, the whole corpus luteum was exposed, and the external projection was seen to form only a small part of the entire body. It measured nine-sixteenths of an inch in its long, and three-eighths of an inch in its short diameter. It consisted of a tolerably firm, solid mass, of an ovoid shape, and of an exceedingly rich orange-yellow colour, which was uniform throughout. There was no cavity anywhere, but about the edges of the section might be seen the narrow, nearly straight line ran irom the most projecting part, a considerable distance into the interior of the body. The projecting part appeared to have been folded doAvn toward the lower extremity of the ovary, and confined in that position by the contraction of the investing membranes. (PI. IV., Fig. 3.)
Ovary of a cow, eight months pregnant ; showing the promi- marks of previous Compression and foldnent portion of a corpus luteum.
The substance of the corpus luteum was of a highly organized appearance. No vessels, however, were to be seen in it, except where they ramified in the furrows about its edge. Its relations to the surrounding tissues were the same as in preceding cases.
The right ovary was one and three-quarter inches in length. Its surface was like that of the other, showing one Graafian vesicle, about one-fourth or three-sixteenths of an inch m diameter, and many other smaller ones. On the free edge of the organ was an orange-yellow spot like that on the left, only not projecting. The corpus luteum which was situated beneath was entirely similar to that in the left ovary, except in being somewhat larger, and in having near its centre a small, narrow, white, radiated cicatrix, from which a faint whitish line ran to the external surface of the corpus luteum, on the free edge of the ovary. (Fig. 22.)
There were no other marks or spots observed on the surface of the ovaries indicating corpora lutea.
Ovary of a cow eight months pregnant.
It is evident, from the foregoing Fig. 22. observations, that the formation of the corpus luteum in the cow is very similar to that whicli takes place in the human female ; the diiference between the two consisting only in details, while the general plan remains the" same. There is in the first place, no yellow matter deposited, as some writers have maintained, previous to the rupture of the vesicle ; but, at the time when this occurrence takes place, the walls of the vesicle are smooth and membranousj presenting indeed altogether their usual appearance.
Soon afterward, however, a growth takes place from the inner surface of the cavity, and assumes the same convoluted form as in the human species. In the cow, however, this new growth is much more rapid and abundant. It soon completely fills and distends the cavity of the vesicle, and even sprouts luxuriantly from its aperture, in the manner of a fungous growth ; forming a very noticeable protuberance on the surface of the ovary. The peritoneum is soon reproduced over this protuberance, and the sides of the tumour are covered with vascularity. The substance of the corpus luteum, which was at first of a pale undefined hue, like recent lymph, has now acc[uired a strong yellow colour, and presents a solid mass of an ovoid shape, with its centre occupied by a pale, radiated cicatrix, the result of the closino- tofrether of the vesicular parietes.
The corpus luteum seems to attain this condition in about two weeks after the discharge of the ovum. After that period it follows a retrograde course, which is characterized by the following changes. The central cicatrix becomes more and more indistinct. The yellow matter changes its colour to a dull yellowish-brown, and afterward most commonly to a brick red ; though there is reason to believe that the latter alteration does not invariably take place. At the same time it contracts a more intimate adhesion with the neighbouring parts, and its investing membrane becomes confounded with the adjacent areolar tissue; so that at last it appears as a mere spot, or islet, in the ovarian substance, presenting to the eye a reticulated appearance, and incapable of being separated from the ovary as an entire body. There are usually several of these obsolete bodies, of different sizes, to be seen in the ovaries together, provided the animal is not pregnant ; their situations being indicated by small red spots on the surface of the ovary.
The difference in aspect between the corpus luteum following an ordinary ovulation, and that which accompanies pregnancy is not so striking in the cow as in the human female. This is apparently owing to two circumstances; first, that in the cow there "is, at the time of the rupture of a vesicle, but little or no hemorrhage into its cavity ; and secondly, that the groAvth of yellow matter which takes place afterward, is so much more rapid and abundant. It will be recollected that one of the most important distinctions between the human corpus luteum of menstruation and that of pregnancy was the thickness of its yellow wall, as compared with the central coagulum; and since in the cow there is little or no central coagulum, and since the yellow wall always becomes thick enough to fill the cavity of the vesicle, the above distinction cannot be here applied. Nevertheless, there is another equally important distinction which still remains applicable, viz., the longer duration of the corpus luteum, when its growth is modified by the occurrence of pregnancy. It has been demonstrated (Obs. XVI.) that, at the time of the rupture of a vesicle, the corpus luteum of the preceding ovulation has already become distinctly retrograde ; its colour considerably lighter, and its size reduced. Before the new vesicle has assumed entirely the appearance of a corpus luteum, the old yellow body (Plate III., Fig. 2, a) has become still farther atrophied ; its cavity entirely obliterated, its central cicatrix indistinct, and the whole body reduced to not more than a quarter part the size which it had at the period of its greatest development. (Plate III., Fig. 4.) It appears, therefore, to be sufficiently well ascertained that, in this animal, the corpus luteum ordinarily reaches its maximum of development in about two weeks after the rupture of the vesicle, and that a period of three Aveeks longer reduces it to the condition of a small, obsolete, yellowish or brick-red spot, without any investing membrane, and not presenting any of the ordinary characteristic appearances of a corpus luteum.
On the other hand it is certain, that if the rupture of a Graafian vesicle is followed by pregnancy, the corpus luteum does not attain its greatest size till about the middle of the seventh month (Obs. XXIV. and XXV.); and that at the termination of the eighth month (Obs. XXVI.) it is still of large size, and sometimes forms a very remarkable prominence on the surface of the ovary. At the same time, the obsolete bodies which mark the situations of still older ruptures gradually disappear from the ovary; so that, toward the latter periods of gestation, the corpus luteum of the last rupture is the only body of the kind to be found in the organ. In those cases, however, in Avliich impregnation has not taken place, it is not at all unfrequent to find beside the principal body, six, seven, or eight others, in different stages of retrogression.
The substance of the corpus luteum of pregnancy, also, is always of a soft, rich, pulpy consistency, and its colour a very deep orangeyellow; while in the unimpregnated animal its texture is firmer, and it presents an orange tinge only for a very short period of its existence; the colour being, for the most part, a very light stone-yellow.
Numerous observations on sheep have demonstrated the fact, that a similar distinction exists in them between the corpus luteum of ordinary ovulation and that of pregnancy. The rupture of the vesicle in this animal, as in the cow, is unaccompanied by any considerable hemorrhage, and the new growth is afterward produced with a similar rapidity and luxuriance. Its colour is not by any means so brilliant as in the cow, but is a dull yellowish white. After the bodies become completely obsolete they present a dusky brownish spot, without any tinge of red. In the retrograde corpus luteum of the sheep, there is sometimes to be found a cavity containing a few drops of clear fluid, and a lining of transparent lymph. This, however, is only an occasional appearance, and seems to be owing, as in the human subject, to the accidental closure of the mouth of the vesicle, before the complete coalescence of the walls in its interior.
With these exceptions, the growth and atrophy of these bodies follow nearly the same course as that which has already been described. At the time of the rupture of a new vesicle, the old corpus luteum, of a fortnight or three weeks previous, has become much reduced in size, and considerably paler in hue; while the occurrence of pregnancy causes it to remain for a long time nearly undiminished in size, and unchanged in colour.
The microscopic appearances of the corpus luteum are nearly the same in the cow and sheep; the only difference consisting in the amount of oil present, which is quite abundant in the former, and rather scanty in the latter; at least, until a late period of its development. There are to be seen, in the substance of the convoluted wall, an abundance of pale, roundish, or irregularly elongated cells, faintly granulated, sometimes containing minute drops of oil, and often, particularly in the early periods, circular or oval nuclei, with nucleoli.
Fig.23. Cells from a corpus luteum of the cow, at its maximum of development. (Obs. 21st.) Each division of the scale is about .0004 of an inch.
Cells from the corpus luteum of a cow, six months pregnant. (Obs. 24.) Same scale.
The nuclei may sometimes be seen floating about the field, unprovided with any cell-membrane. While the corpus luteum is in its early stages, there is also a large quantity of the spindle-shaped cells of areolar tissue in process of development, to be seen in intimate connexion With the other elements.
As the corpus luteum grows older, the spindle-shaped cells are less numerous, and the oil, which is evidently secreted by the larger cells, becomes more and more abundant, as the latter are atrophied and disappear. Finally, the whole field is occupied by globules of oil, of various sizes, Avhile the cells are too few, or too indistinct to attract the notice of the observer.
Fig. 25. Cells from the corpus luteum of an unimpregnated ewe, in an early stage of its development. Same scale.
Fig. 26. Cells from the corpus luteum of an unimpregnated ewe, which was commencing to become retrograde. Same scale.
Appendix
Since the foregoing essay was written, and delivered to the Committee, I have met with the two following passages relative to the corpus luteum, which contain the same or similar views with those expressed in the present memoir. The first extract is from a work by Drs. Kirkes and Baly, published in London, in 1848, and entitled a "Supplement to the Second Volume of 3Iiiller's Physiology." I am indebted to Prof. 0. W. Holmes for calling my attention to the passage in question. It is as follows : — (page 55.)
" In the figures given by Sir E. Home and M. Bischofi" of corpora lutea formed under these circumstances (without impregnation), it is evident that the growth of the yellow substance has proceeded to such an extent as to protrude from the orifices of the ruptured follicles, after filling their cavities. These are certainly corpora lutea which could not be distinguished from corresponding bodies of the same stage of development in the ovaries of impregnated animals. In the impregnated animal, however, the corpus luteum continues to increase in size after the orifice in the follicle has closed ; and whether this is the case in animals which are not impregnated is doubtful. It is probable that if the ova have not been fecundated, the state of orgasm of the ovaries and Graafian follicles, which arose during the condition of heat, subsides, and that the corpora lutea then, instead of continuing to grow, quickly shrivel and disappear."
" With regard to the human female," the author proceeds to remark, " the limitations with Avhich the rule may be admitted are greater," and, although he recognizes the fact that corpora lutea formed in consequence of menstruation are, generally, smaller than those following pregnancy, no other distinction between them is mentioned, than their difi"erence in size. Even this is not considered as altogether reliable, and the author comes accordingly, to the following conclusion. " If, in addition to the foregoing facts and considerations, the varieties in size of the corpora lutea formed during pregnancy are borne in mind, it will be seen that cases can seldom occur where the mere presence of one of these bodies can be taken as a proof of previous impregnation," (p, 56.) 'The writer, therefore, does not admit entirely the difference of development in the human corpora lutea of menstruation and pregnancy as forming a distinction between them ; and he only considers it as " probable" that such a distinction exists in animals.
The second extract, however, contains expressions more definite and satisfactory. It is from Lonc/et's Physiology, Paris, 1850, vol. ii. p. 88, De la Gdndration.
"At the same time," says Longet, "we must distinguish Uoo kinds of corpora lutea ; those which result from the cicatrization of a follicle, after the spontaneous expulsion of an ovum, without any subsequent conception ; and those which are produced by the same processes, after the expulsion of an ovum followed by conception and especially by gestation. Those belonging to the first class rapidly pass through their different stages, never attain a high degree of development, are much inferior to the others in size, rapidly assume the yellow coloration, fade again in a few days, and in the course of one or two months became retracted and completely concealed in the ovarian tissue. The second species of corpora lutea, participating in the congestion and functional activity, which are established in all the sexual organs during gestation, attain a size sometimes greater than that of the ovary itself, and pass so slowly through the different stages of their development and atrophy, that they are still perceptible at the termination of pregnancy ; they gradually diminish in size, in proportion to the growth of the foetus, and the approach of the end of gestation."
The above statements, by Longet, it will be seen correspond entirely with those brought forward in the present essay. They are given by him, however, altogether under the form of general deductions ; and the reader is not supplied with any series of observations which would convince him of their reliability. It is in the foregoing pages alone, so far as I am aware, that the difference of the two species of corpora lutea has been absolutely demonstrated ; so that the distinction between them no longer rests on bare assertion, but on the evidence of recorded facts.
J. C. D.
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Dalton JC. Prize essay on the corpus luteum of menstruation and pregnancy. (1851) Philadelphia: T.K. and P.G. Collins.
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| Corpus Luteum 1851: Part 1 - Corpus Luteum of Menstruation | Part 2 - Corpus Luteum of Pregnancy | Part 3 - Observations on Animals | Plates |
