40 ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 



stage to the Peters stage, its center becomes filled with more fluid and separates 

 the fibrillar connective tissue, leaving them as magma fibrils, so that we must look 

 upon the ccelom of the older embryologists, identical in structure with the center 

 of the villi, as the true ccelom, which this substance with its cells is pushing aside, 

 as described by Retains. In pathological specimens, however, the true ccelom does 

 not develop normally, but the magma simply becomes thickened, making it appear 

 as though the ccelom were filled with the magma. This conception of the magma 

 allows one to interpret properly a section of the chorion and the ccelom as shown in 

 my figure 169 in the Handbook of Embryology. It is quite clear, upon second con- 

 sideration, that the magma fibrils are simply prolongations of the mesoderm cells 

 of the chorion. We can see in this arrangement a repetition of the ordinary develop- 

 ment of the connective tissue fibrils, as illustrated by a section through any part 

 of the embryo. In fact, this is well brought out in the human chorion, if it is well 

 stained by the Van Gieson method. I have taken the trouble to make a careful 

 examination, by this method, of a chorion containing a normal embryo and one 

 containing a pathological embryo. 



Specimen No. 808 contained a practically normal embryo with a dense reticular 

 magma filling one portion of its cavity. Sections were stained with the Van Gieson 

 stain and drawn in black, as given in plate 11, figure 3. At the point from which 

 the illustration is taken the chorionic wall is not very compact. It is composed of 

 loose fibrils intermingled with cells. The fibrils, which are stained intensely red, 

 radiate from the cells, forming a dense connective-tissue framework, as may be seen 

 in sections of the umbilical cord or villi. Just surrounding the cells, or rather the 

 nuclei, the fibrils are more marked, having a tendency to grow in parallel lines; in 

 other words, they are more highly developed, and as the chorion becomes older we 

 find that all the fibrils of the chorionic wall undergo similar changes. As long as 

 the magma fibrils fill the cavity of the ovum a condition is maintained like that 

 shown in the figure, but as the amnion pushes the magma fibrils up against the 

 chorion, they form a layer which blends with it. This is the ordinary development 

 of this process. 



When the cavity of a pathological ovum is filled with a dense magma, or, as it is 

 usually put, when the ccelom is filled with a dense reticular magma, it also becomes 

 fibrillar, and this is well shown in No. 402, which is a typical pathological specimen. 

 Here the fibrils radiate from the chorionic wall and are also sharp and wavy, having 

 a tendency to run parallel with one another. We have here a thickening of the 

 magma in its normal position, without a development of the amnion. There is an 

 excessive growth of the magma fibrils, which in this specimen radiate from the 

 chorionic wall to the center of the ovum. As specimens like this continue to grow, 

 the delicate connective tissue fibrils of the magma become intermingled with flakes 

 of a peculiar tissue which take on an intense stain in hsematoxylin. Sometimes a 

 few of these flakes are found in specimens containing normal embryos, but in numer- 

 ous pathological specimens large areas of these flakes are seen. In tubal pregnancy 

 they are often present, and at first were described as large plaques of mucin, "pos- 

 sibly representing a degenerate yolk sac," but upon further study it was soon found 



