DEPARTMENT OF EMBRYOLOGY. 105 



nection with a normal ovary, the latter containing four recent corpora 

 lutea. Within the tube was found a normal ovum. The opposite 

 cornu had a rudimentary Fallopian tube ending near the convoluted 

 end of a Wolffian duct. The latter possessed the characteristic of an 

 epididymis, as regards both its form and its relation to an adjoining 

 testis. The testis was normal in structure, with the exception that 

 germ cells were totally lacking. Dr. Corner does not attempt to ex- 

 plain the inhibition in development of the male germ cells in such cases. 

 In our report in Year Book No. 17, reference was made to the obser- 

 vations of Professor A. W. Meyer on the occurrence of the process of 

 hydatiform degeneration. He showed that instead of being a rare 

 condition, it is one of the most common forms of degeneration of the 

 chorion and constitutes an important factor in the cause of abortion. 

 This study has been continued by Dr. Meyer and a complete report has 

 been published of all the instances of hydatiform degeneration found in 

 uterine and tubal specimens of the Carnegie Embryological Collection. 

 It is Dr. Meyer's conclusion, from the large series of cases examined by 

 him, that this type of degeneration is usually associated with an abnor- 

 mal decidua and changes suggestive of endometritis, resulting in an 

 abnormal implantation. He is confirmed in this view by the higher in- 

 cidence of hydatiform degeneration in tubal specimens, reasoning that 

 the mucosa of the tubes forms an unfavorable place for implantation 

 and thus leads to an abnormal nidification. He finds scant evidence 

 that it is the result of primary germinal defects, and in this respect he 

 deviates from the trend of the observations of Dr. Williams and Dr. 

 Corner. 



THE COLLECTION. 



During the past year the collection of human embryos has been 

 considerably increased, there having been 760 accessions between Sep- 

 tember 1, 1919, and September 1, 1920. This is the largest number 

 we have ever received within one year. The increase is in large part 

 due to the cooperation established between our laboratory and officers 

 of the Health Department of Baltimore City. Through this source we 

 are now receiving a large number of fetuses of the later months of preg- 

 nancy, which period of development has heretofore been poorly rep- 

 resented in the collection. We are also greatly indebted to a number 

 of practicing physicians of Baltimore and other cities, through whose 

 generous efforts many valuable specimens have come into our pos- 

 session. Owing to the rapid increase in our material, the problem of 

 its care and storage is becoming a pressing one. In order that it may 

 be kept readily available to ourselves and other workers, additional 

 space will have to be found in the near future. 



The value of the collection and of our associated facilities has made 

 itself apparent in the number of visiting investigators who have come 

 for longer or shorter periods during the year to utilize this laboratory 



