Paper - A study of the causes underlying the origin of human monsters 16
|Embryology - 16 Oct 2019 Expand to Translate|
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Mall FP. A study of the causes underlying the origin of human monsters. (1908) Jour, of Morphol., 19:
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A Study Of The Causes Underlying The Origin Of Human Monsters
Pathological Embryos of the Fourth Week
No doubt the reader has noticed that the embryos grow more and more resistant as they become older, and this condition continues to a more marked degree in those of the fourth week. In embryos of the second week pathological changes in the chorion were followed by a partial or com— plete destruction of the amnion and embryo, while in those of the third week it is not always the same organ or tissue which resists the inﬂuence longest. However, the brain and heart are recognizable in most of the specimens.
When we reach the fourth week we ﬁnd that the main change in the normal embryo is due to the addition of the peripheral nervous system, which is associated with a sharper delineation of the organs; they begin to assume some of their adult characteristics. A normal type with which to compare these changes is seen in embryo No. 2, which has become a standard. In my description of pathological specimens of the fourth week I shall keep this embryo constantly in mind. .108 MALL. [Von XIX.
The specimens of the fourth week cannot be considered in the sequence given in Table IX, for a number of them are straightened and, therefore, measure larger than others that are more advanced in development but curled up in their natural shape. This, I think, is well shown in the various illustrations. However, it is clear that Nos. 334, 285, 312, 336 and 347 are decidedly larger than the rest, about the same stage of development as the normal specimen No. 2, and, therefore, about twenty-eight days old. The rest of the specimens are younger and belong to the beginning of the fourth week. In the first and younger group some of the embryos that are straight and measure 8 mm. are a little earlier than others that are but 5 mm. long.
Specimen. Embryo. Chorion, 3 3’: 52¢ 2 mm mm. days
|His (D2)||5||20 X 15|
|21 His (R)||5||22|
|No. 16||6||24 x 18|
|No. 24:||6||40x40 5:|
|No. 173||25x15xxo 54|
|No. 116||5-5||28 x 20 x IO 55|
|No. 18||7||18 x 18|
|No. 187 s||7||64|
|His (B)||7||25 x 22|
|His (Stt)||7.75||2: x :7 57|
|No. 208||8 nzxuxn 49|
No. Tggggggf gigggggog Meg-giual Changes in Chorion. mm. mm. days. 122 5 2oxr6x6 65 Atrophic. 136 5 14 x II x 6 56 Atro hic. 150 5 35 x 30 x 10 But ew villi. 291 5 Atrophic. 398 5 , , 3 34 5 5o x 40 x 30 4 wks. F 1bl'0uS. Inﬁltrated with leucocytes and syncytium. So 5 24 x 18 x 8 ‘Small amount of mucoid mass between the villi. 4°! 56 340 6 297 6 3 mo. _ 104 7 35 x35 x 15 35 Atrophic. 3359 4th8w . 35 x 25 x 15 IO wks. Fibrous. o no 8 46 x 30 x 30 82 Fibrous. Invaded by leucocytes. 141 8 40 x 30 x 20 78 Fibrous. From same woman No. no was obtained. 275 8 4o x 30 x 25 2 mo. Fibrous. 285 8 45 x 3 5 x 3 5 7 2 Very ﬁbrous. Atrophy. 289 8 4 wks. 312 8 25 x 15 x IO Fibrous. Invaded by leucocytes. 347 8 40 x 3 5 x 30 Fibrous. Inﬁltrated by leucocytes. 336 8 35 x 25 X 15 Hyaline and ﬁbrous.
Specimen No. 136 contains in it a normal embryo of the fourth week, but its enveloping chorion is too small for its age. The villi of the chorion are ﬁbrous, but contain a large number of blood-vessels which are well distended with blood. The syncytium is very active and no doubt provided well for the embryo. The only marked changes in this specimen are the ﬁbrous chorion and the excessive amount of magma reticulé in the coelom. Possibly the inequality of things may have brought about the abortion.
Of the remaining specimens of the ﬁrst group, No. 312 shows the least amount of change in it. The embryo, however, is straight, shows three gill arches and some myotomes. The spinal cord can still be outlined in the tissue of the body, which is well ﬁlled with round cells.
Generally, in the rest of the embryos, the brain is solid, the spinal cord dilated, the blood-vessels more or less distended with blood and the remaining organs and tissues pretty well dissociated. These changes are least marked in No. 297, which, however, is a pretty typical one. The outlines of the precartilages can still be made out, and some of the peripheral nerves are present. The lower jaw is disintegrating, which naturally brings the distended medulla closer to the midventral line of the head. All these changes are more pronounced in No. 340. The dissociation of the organs is here quite complete, with some indications of growth of the mesodermal tissue, including the precartilages. In the spinal cord there is a tendency toward regeneration, provided the curious bands of cells seen here indicate it. The dissociation of the larger blood-vessels is practically complete, but their outlines can still be seen, although many round cells ﬁll the surrounding tissue. This condition is practically completed in the embryo of specimen No. 275, in which but few of the tissues are recognizable.
In specimens Nos. I04, I10 and I4I the destruction of the embryos is pretty well under way, showing what may be the fate of embryos of this sort. The details are much the same in the different specimens, and may be summed up in the words “more advanced.” That Nos. I10 and I4.I are from the same woman about a year apart is especially noteworthy. The woman was suffering from leucorrhoea and in general the ova show the same changes within them. Nearly all of the villi have been destroyed, and the main walls are ﬂeshy and are invaded by leucocytes. The embryos are dissociated and atrophied. That the process was slow is indicated by their menstrual ages. In one the amnion is destroyed entirely and in the other it is greatly dilated, nearly ﬁlling the entire cavity of the chorion. That two specimens coming from the same woman should show the same changes in them indicates that the cause of the trouble lies in the diseased condi tion of the uterus. There are a number of other specimens which corroborate this conclusion.
During the fourth week of development the preskeletal tissues make their appearance, and through this change the embryos naturally fall into the two groups under which I am discussing them. The mesenchyme also becomes more resistant and does not dissociate so easily. The peripheral nerves are well laid down and the premuscle tissue is making its appearance. Thus we have new conditions by which we can recognize the time at which development was arrested; these naturally inﬂuence secondary changes in the embryo. In these specimens hydramnios is nearly always found, and since the embryos usually become markedly smaller when their development is arrested it is rational to conclude that hydramnios is produced by a continued growth of the amnion and chorion when the development of the embryo has been arrested. I have found no evidence in favor of the theory that hydramnios is due to arrested development of the amnion and dwarﬁsm of the embryo. Were this the case we should ﬁnd bones and cartilages in my specimens of the fourth week. In the specimens given in Table IX we have four weeks’ embryos in eight weeks’ chorions, not degenerated eight weeks’ embryos in eight weeks’ chorions. The four good specimens (Nos. 347, 285, 336 and 334) of the end of the fourth week are of different degrees of degeneration and form an excellent continuous series. No. 347 is from an ovum in which the mesoderm of the chorion is ﬁbrous, the syncytium being scanty and mixed more or less with pus. The changes within the embryo are well marked, the brain being dissociated and solid and the medulla and cord are dilated. The blood-vessels are well marked, dilated and ﬁlled with blood, which is just beginning to inﬁltrate into the surrounding tissues. The other organs are just beginning to dissociate. The precartilage is well marked, however, and the rest of the mesodermal tissue has in it many round cells which seem to have come from the blood. Many of these cells are in the pleuro-peritoneal cavity. Conditions are advanced markedly in No. 285. Here the menstrual history tells us that the pathological process has been under way for a number of weeks. The mesoderm of the chorion is ﬁbrous and between the few villi covering it there is much mucus rich in leucocytes. The embryo is atrophic, the tissues, however, being still active, although dissociated. The brain and head are reduced in size, the medulla is solid and ﬁlls the region of the face, and the cord is dilated and its walls are folded upon itself. The organs are more dissociated than before, the large blood-vessels and the heart being greatly dilated and ﬁlled with blood. The precartilages and peripheral nerves are well marked and the remaining tissue is pretty well ﬁlled with round cells. Most of the epidermis is intact.
The two specimens just described show to what extent an embryo four weeks old may dissociate when its nutrition is partly cut off. In the next specimen (336) the amnion did not continue to dilate as well as it did in Nos. 285 and 347, but remained clinging to the embryo, as is the case normally at this time. However, it is pretty well destroyed, being partly inﬁltrated with embryo blood-cells. The coelom is well ﬁlled with granular magma, in which there are many migrating cells. In form the embryo is curled upon itself and distorted. Within the central nervous system is dilated and the walls -are folded upon themselves. The liver is completely inﬁl trated with blood. Mesodermal tissues seem to be normal. What is especially noteworthy is the condition of the vascular system. The heart walls appear normal and the vascular system is well proportioned and ﬁlled with blood. It appears as if it had functioned until the abortion took place. The vessels from the embryo through the umbilical cord to the chorion are cut off and the enlarged omphalo-mesenteric vessels seem to take their place. The walls of the yolk sac are necrotic, but have in them large blood-vessels, which on one side spread over into the chorion. The old original circulation has re—established itself and is now connected with the chorion in this roundabout way. There are in the chorion two kinds of capillaries, degenerate ones which are connected with the umbilical vessels and new ones which communicate with the omphalo-mesenteric vessels.
The other specimen of the fourth week is the remnant of the embryo from No. 334. Here the destruction is quite complete, only fragments of a four weeks’ embryo being found in a small space of a large mole. The piece shows dissociated organs of an embryo much like No. 285.
These specimens give the beginning and the end of dissociated embryos during the fourth week, with an attempt to remedy the difficulty in one specimen (No. 336), and the almost complete destruction in another (No. 334). It is probable that the primary trouble in No. 336 lay in the umbilical cord.