NODULAR CYEMATA. 75 



the term nodular as synonymous with amorphous, for he characterized nodular 

 embryos as "specimens in which no organs are visible. " Furthermore, he believed 

 that nodular specimens are without a cord. 



With the exception of a portion of a full-term specimen which we owe to the 

 generosity of Dr. Morris Slemons (No. 1682, fig. 15) and which was described 

 by him in 1917, none of those in this group measures over 5 mm. in length. Indeed 

 it is unlikely that any other specimen strictly belonging here exceeds a length of 

 4 mm. Consequently, all embryos from among the first 1,000 accessions which 

 unquestionably are nodular in character have a maximum length of less than 4 

 mm. But this group is distinguished not only by the small size of the embryos, 

 for that might imply that they merely are very young. The latter is the case, 

 but their menstrual ages nevertheless are much greater than their size would 

 indicate; nor are they all in any sense immature, normally developed embryos 

 which merely have been universally and equally retarded in their growth. They 

 undoubtedly have been retarded, but this retardation has been decidedly unequal. 

 Moreover, they not only have been stopped in a very early stage of development, 

 but they had not reached that stage in a wholly normal way. 



Although one would not suspect it from external appearances alone, this 

 group of the pathologic is by far the most interesting. Some of these specimens 

 show an astonishing simplicity in form and structure. Perhaps it was this fact 

 which caused His (1891) to doubt whether they really were remnants of the whole 

 embryo. His query is justified by the form and microscopic structure of many 

 of them, as is so well illustrated by Nos. 2288, 1369, and 651#, shown in figures 

 16, 17, 18. 



Next to the small size of the cyemata in these abortuses, the disproportion 

 between their size and that of the chorionic vesicles in which they are contained 

 is what attracts one's attention. This lack of correspondence is so great that the 

 chorionic vesicle may be not only 10 or 20, but even 50, 60, or 70 times as large 

 as the cyema; nor should the occurrence of such disproportions be surprising, for 

 if the cyema can wholly vanish it stands to reason that infinite disproportions 

 must occur as it becomes smaller and smaller in size, to finally disappear altogether. 

 For, even if the body of the cyema eventually were to disappear by solution, it 

 would still be true that its development could be checked at any time between 

 the appearance of the first rudiment and the completion of growth at the time 

 of birth. A similar disproportion in size not infrequently exists between the 

 amnion and cyema. The amnion not infrequently is entirely too large for the 

 embryo, but nevertheless much smaller than the chorion. Hence it seems that 

 the amnion, too, must have considerable power of independent growth in spite 

 of the absence of vessels in its walls. In some instances it was found to contain 

 blood-vessels, however, and in several cases large cyst-like dilatations were present, 

 some of which may have been the result of fusion of portions of the adjacent walls. 



The body is by no means the most resistant of the strictly cyemic structures, 

 however. The umbilical vesicle or the cord, or indeed the allantoic stalk of the 

 amnion, may survive it. Such cases do not belong in this group, but since it is 



