20 HUMAN MAGMA UKTICn.K IX NORMAL AM) I'A TIK H.OCICAI, DKVELOPMENT. 



elusion must be drawn that the fragmented cells arise from the mesoderm cells. 

 The epidermis covers tlie whole embiyo. The primary change in this specimen is no 

 doubt in tiie mesoderm, for all the rest of the embryo appears normal. That the 

 equilibrium was overthrown is indicated by the necrotic amnion and the great 

 amount of reticular magma in the exoccelom. ^yhat is especially interesting in this 

 specimen is the partial destruction of the anmion, which l:)rings the embryo directly 

 in contact with the pathological magma of the coelom. 



Embryo No. 12, which has been just referred to, may also be discussed in this 

 connection. It was questionable for a long time whether or not the embryo was 

 normal, as the villi and contents of the coelom and embryo are beautifully preserved 

 and show no pathological change. However, more careful consideration of the 

 specimen shows that there are a few fibrinous masses between the villi, w^th every 

 indication of uterine inflammation and infection. The extent of the reticular magma 

 is more pronounced than usual, aiul it was necessary to dissect it away before the 

 embryo could be isolated sufficiently so that it could be well seen. The head is no 

 doubt atrophic, and I am fully convinced that this part of the embryo must have 

 undergone pathological changes a short time before the abortion. 



Specimen No. 318 is much like No. 250. The ovum, measuring 20 by 18 by 11 

 mm., is covered with villi which ajijiear to be };)erf(Ttly normal. Ui)on ojiening, it 

 was found to be filled with stringy magma, on one side of which was eml:)edded an 

 embryo 2.5 mm. in length. The head is sharply outlined, but th(> embryo seems to 

 continue directly with the umbilical vesicle, leaving an atrophic tail. Sections show' 

 that the amnion over the head has dissolved, leaving a picture very much like that 

 shown in No. 250. ^^'e have here a small embryo with a very large coelom, the ovum 

 being moderately filled with reticular magma and a small embryo only partly 

 covered with the amnion. No. 543 is another embryo of the same type. The 

 magma is a little denser than in No. 318. The chorionic villi are developed, but 

 markedly pathological, as the photograph shows. The embryo within is 3 mm. 

 long, lying (juite free within the mass of magma. It is covered bj' a ragged amnion; 

 that is, the amnion is partly destroyed. 



An interesting specimen in this connection is No. 402, which is partly described 

 in my paper on monsters, since the issue of which the embryo and chorion have been 

 cut into serial sections. The villi of the ovum are not well developed, and they are 

 distributed irregularly over the surface. The coelom is filled with reticular magma. 

 The embryo is club-shaped, the head being much too far advanced for the body. 

 The umbilical vesicle is normal in size; the heart is well outlined, and the extremities 

 are just appearing. Sections show that the amnion is greatly distended. Sections 

 of the chorion were stained with cochineal and \'an Ciieson, and show beautifully 

 llic fibrillated structure of the chorionic membrane. These fibers take on red 

 stain, as do those of the reticular magma. The two are continuous, as shown by the 

 illustration on i^late 3. figure 3. In fact, this continuity is much more i)ronounced 

 in pathological than in normal specimens. 



Specimen No. 533 (plate 2, figure 3) shows a more ad\ anced stage of an extensive 

 development of reticular magma. The vilh of the ovum appear to be normal and 

 the reticular magma is verj- dense. Between the meshes there are a number of 



