366 Maximilian Herzog. 



it bad been immersed for twenty boiirs. It bad been discbarged 

 by a bealtby woman on November 5tb, presumably as a result of 

 tbe disturbance effected by coitus ^November 3d to 4tb. Tbe speci- 

 men was bardened in absolute alcobol and sectioned in paraffin. 



Attached to tbe inner surface of tbe chorionic vesicle, two smaller 

 vesicles were found. Tbe larger, "torn and collapsed," was at- 

 tached to the chorion "definitely only at one point," but the smaller 

 was bound to the ohorion by mesoblast strands, with which it was 

 closely surrounded. The two vesicles were separate from one an- 

 other. Bryce and Teacher consider that "after careful considera- 

 tion of the sections and model the conclusion is inevitable that the 

 larger vesicle represents the amnio-embryonic cavity and the smaller 

 the entodermic vesicle or future yolk sac." (Page 26.) However, 

 the embryo is so badly preserved that even this conclusion may 

 be questioned, and on page 34 Bryce and Teacher discuss a different 

 interpretation. In the very, young embryo to be described in the 

 present communication the yolk sac vesicle is larger than that of 

 the amnion, and is attached to the chorion only at one point. 



Jung's ovum, fully and lucidly described in his recent monograph 

 already quoted, is one of the very youngest and best preserved now 

 on record. It was, however, not obtained in situ, but as the result 

 of a curettage of the uterus, and was preserved in 80 i)er cent, 

 alcohol, which, according to Jung's own comparative studies, is not 

 very favorable for the fixation of young human ova. In spite of 

 this, its fixation has been very satisfactory, and karyokinetic figures 

 have been preserved in the trophoblast, the decidua, and the em- 

 bryo itself. According to the description given of the latter (p. 102, 

 Jung, I.e.), the "Embryonalgebilde" was found in nineteen sections 

 each on an average of 13 microns thick, making a total length of 247 

 microns. However, as Jung states, some of the sections containing 

 tbe embryo had been lost and an attempt at reconstruction had to be 

 given up as futile. The whole "Embryonalgebilde" is said to be en- 

 closed within a thickening of the mesoblast in the interior of the ovum, 

 attached to its basal surface. "Within the mass of mesoblast we see 

 the ectoderm shield ('Keimscheibe'). In transverse section it is 

 a crescentic formation, with its concavity towards the basal side 



