Embryonic Development in Man. 393 



take part extensively in this process of fusion. It appears that the 

 syncytial masses after penetrating into the border zone have a 

 tendency to break up into cells. Individual detached pieces of 

 syncytium can often be recognized as such by the deep eosin stain 

 of the protoplasm and by the rods lining the external surface. How- 

 ever, other portions of what appears to be detached syncytium in 

 the border zone have lost their characteristics. It is in the border 

 zone and only in it, in our sections, that marked degenerative pro- 

 cesses are seen, and these appear to be mostly confined to cells and 

 tissues of maternal origin. In the border zone are also seen larger 

 protoplasmic masses containing several generally pyknotic nuclei. 

 We think that these are detached degenerating portions of the tro- 

 phoblast; whether they are portions of the "Grundschicht" or the 

 "Deckschicht," we are not able to decide. We believe that the large, 

 irregularly round cells with vesicular nuclei are derived from the 

 syncytium, since their protoplasm stains very deeply with eosin. 



Peters describes numerous and jDrofound changes in the tropho- 

 blast. These changes Marchand has already considered to be patho- 

 logic and probably due to the fact that the woman from whom this 

 ovum came died from the effects of a rapidly fatal dose of caustic 

 potash. However, Marchand also believes that the extensive pres- 

 ence of blood in the trophoblast of Peters' ovum is abnormal. In 

 this respect he is mistaken, since our own ovum shows the identical 

 condition. 



It appears from Peters' monograph (p. 50 and p. 51) that he 

 found in plasmodial masses and in the syncytium more or less normal 

 and also much changed fragmentary red and white blood corpus- 

 cles. He describes this quite fully, and he draws from this observa- 

 tion the remarkable conclusion that the maternal blood with its own 

 corpuscular elements contributes to the formation of the syncytium. 

 Neither Bonnet nor Jung have found anything like this. 



Not a trace of any such process or condition can be found in our 

 own ovum. Nowhere were red blood corpuscles in toto or in fragments 

 seen included in the trophoblast elements. It is quite probable that 

 in Peters' case the profound intoxication with fixed alkali had so 

 changed the red blood corpuscles, had, as we would express it to-day, 



