THE ANATOMICAL RECORD VOl. 11. OCTOBER, 1908 No. 7 Note on Pathological Changes Found in the Embryo Pig and its Membranes. BY HENRY S. DEICISOR. From the Anatomical Laboratory of J o b Hopkins University. Several years ago Dr. Mall placed at my disposal the uterus of a pig containing three normal and six pathological embryos which in general appeared to be much alike. The normal ones measured 15 mm. from crown to rump, and the pathological ones were somewhat less than half as long. It had been my intention to investigate the frequency of pathological embryos in the pig and to ascertain whether they are associated with constant changes in the membranes or in the walls of the uterus, and towards this study fifty-seven uteri were examined which gave promising results. Circumstances have prevented me from carry$g the work to a satisfactory conclusion, but the results obtained are perhaps worthy of record. The six pathological embryos are quite characteristic, resembling very much some of those described by Dr. Mall in his recent article on pathological embryos. There is, however, a tendency towards the formation of vesicles along the line of the umbilical cord, as is shown in the accompanying figure. In this specimen there are several vesicles apparently constricted off by twisting and others show secondary constrictions, making them appear like a string of sausages. There is also a thick antenna-shaped tag hanging from the amnion. This tag repeats itself a number of times in the other specimens. The umbilical cord is also generally twisted more or less in all of the specimens, making it appear aa if the pathological embryo rotated within the amnion. The walls of the amnion are thickened, and at first sight amniotic bands appear to be presect, but more careful observation shows that they are only the 254 The Anatomical Record. more thickened walls which do not press upon the embryo, for there is hydramnios in all of the specimens.' Sections of the embryos show a marked destruction and dissociation of the tissues with general dropsy and hydrocephalus. The development is very irregular, but the myotomes, eye vesicla and dorsal ganglia can be recognized. In general the spinal cord is partly filled with romd cells which at points obscure its borders entirely. In all the specimens the heart is nearly destroyed, being replaced by a mass of round cells. In order to determine the frequency of pathological embryos in the pig fifty-seven uteri in various stages of pregnancy were examined, and the results are given in the following table. It is seen that as pregnancy progresses the number of normal embryos diminishes and the number of dead and macerated embryos increases. In these uteri 361 embryos were found, of which 332 are normal, 19 macerated and 10 pathological. The pathological, excluding one cyclops, are 9 in number, and were found in 7 uteri, that is, in about 12 per cent; in each of two uteri two pathological embryos were found, thus indicating that there is a tendency for them to recur in the same uterus. The pathological ova show changes in the membranes that may briefly be designated "fibro-cystic." By this type of change I mean a fibrous modification and thickening of the periccelomic mesenchyme between interspersed cyst-like spaces filled with clear material. Such fibro-cystic 1 .................. ....... ........ Numbtr of chorion with hemorrhagicpatches... Numberwith chalky patches................ Number with epithelial proliferation.. ........ Number with cysts at the junction of the cord with the chorion......................... Number of Number of Nuniber of Number of uteri examined normalembryos found.. .......... macerated enibryos found.. pathological embryosfound 'Mall, Journal of Morphology, xix, 19008. CROWN-RUMP LENGTH OF THE N O ~ Y AEMBRYOE L IN CENTIMETEIUI 11 76 4 1 15 94 3 2 14 79 0 -- - 69 18 18 37 0 0 3 ~ 7 38 1 4 ___ 10 45 2 9 .__ 14 22 7 6 6 11 11 . 20 16 6 9 14 9 2 The Anatomical Record. 255 alteration may attack any number of the ova in a single uterus, and when marked c a w degeneration of the embryo, probably from strangulation of the cord. The chorion immediately adjoining the base of the cord appears to be the seat of election for this disease and is often thickened by a fiui€y mass of fibro-cystic mesenchyme. The cord may be twisted and knotted by fibrous bands which, closing also around the shapes that cysts, produce pedunculated vesicles of various size-bizarre FIQ. 1.-Semidiagrammatic outline of one of the pathological embryoa within the amnion. The cord is twisted and numerous vesicular tags are attached t o it. There is hydramnios; within the outline of the embryo, E, is shown. hang out in the ccelom. The amnion is often thickened, rough and smaller than normal. More often, however, there is hydramnios. Fibrocystic tags project from its outer surface into the exoccelom which contains considerable magma. Constrictions may form about the embryo dividing it more or less completely into segments. The embryo is degenerated and friable, and the tissues are invaded by wandering blood cells. The fibro-cystic change just described occum early in pregnancy. After the death of the embryo the ova quickly degenerate and are not found in later stages. 256 The Anatomical Record. There is, however, an analogous change in older specimens. A few clear cysts are frequently found at the base of the cord in embryos longer than 9 cm. An extensive, rough, fibro-cystic thickening is occasionally present. In one case the embryo with such changes measured 3 cm. less than others of the same uterus. The cyets are often spread over the chorion, forming a-thick mass around the attachment of the umbilical cord to it. Sometimes there are many hundred cysts forming a mass 1.5 cm. thick and 10 cm. in diameter. In the younger specimens hemorrhages are nearly always present in the chorion as the table shows. At first 1 was of the opinion that they were due to rough handling, but their constancy and their tendency to diminish in number as pregnancy progresses makes me doubt this view of their cause. The older ones show siGs of organization with chalky patches which increase as the hemorrhagic patches diminish in number. Chalky changes are very common, especially in the later months. There are three chief forms. One, the commonest, is a white, chalkystreaked succulent polyp involving only the innermost layer of the chorion and flabbily projecting from that surface. Such polz~psmay occur singly or in great profusion and vary much in size, sometimes being as large as 10 cm. in diameter. At the center, on section, there is a considerable infiltration of large round cells surrounded by deeply blue-staining granules arranged on a fine reticular net-work. The peripheral tissue is cedematous mesenchyme. A second form is the “plaque,” that is, a dense whitish plane of chalky deposit situated deeply in the chorion. The third form is a diffuse milky infiltration occurring over the whole chorionic surf ace. The chalky mass is imbedded in gelatinous tissue which often forms a transparent mound by itself. In general these masges form individual islands from 2 to 20 mm. in diameter, but they may form narrow streaks fully 10 cm. long. Epithelial proliferations of the chorion frequently occur in the later months and form wart-like projections which are prone to degenerate in t.he center. Neither the occurrence of these warts nor of chalky changes appears to bear any relation to production of those fibro-cystic changes described above. The warts are generally quite small, 2-5 mm. in diameter, and contain a core of fibrous tissue which later on undergoes hydine degeneration in patches with mucoid tisme between them. In gome instances the hyaline masses coalesce to form droplets and the mucoid tissue disintegrates.