No. 1.] ORIGIN OF HUMAN MONSTERS. 217 
The villi are normal in form, with a very extensive syn- 
cytial layer of cells over them. At points the syncytium 
forms large islands, which can easily be seen with the naked 
eye. Immediately over the vesicle within, an island of this 
kind, a millimeter in diameter, arises from the main wall of 
the chorion and sends processes up between the villi. The 
mesoderm immediately below this island is thinner than the 
rest, making it appear as if the violent growth of the syn- 
cytium took everything before it, but that in the attempt to 
produce new villi the fibrous mesoderm of the chorion would 
not follow. At many points between the villi there is a slimy 
mass of albumen well infiltrated with leucocytes and numerous 
small islands of syncytium, some of which can be followed 
back to their origin from the villi. 
The vesicle within is composed of but one layer of cells, 
those of the mesoderm with blood islands imbedded within it. 
No trace of an entoderm can be made out, although the lumen 
of the vesicle extends into a pedicle which, as a single strand 
of cells, attaches itself to the chorion. 
No. 181. 
Ovum, 18 x 18 x 10 mm. 
Dr. D. S. Lamb, Washington. 
The ovum is filled with reticular and granular magma and 
no remnants of an embryo could be found, although every par- 
ticle which might contain it, with the adjoining chorion, was 
cut into serial sections. The mesoderm of the chorion and 
villi is edematous; the epithelial covering is poorly developed, 
often being composed of but one layer of cells. 
No. 182. 
Head and upper end of the body of an embryo about five 
weeks old. 
Dr. D. S. Lamb, Washington. 
Sections of this embryo show an extreme degree Bf dis- 
integration of the embryo. The brain is converted into a 
mass of cells filling the central canal entirely and extending 
into the surrounding tissues of the embryo, the line of de- 
