86 STUDIES ON PATHOLOGIC OVA. 



the head itself. This is illustrated by Nos. 2173 and 2233, shown in figures 32. 33, 

 and 34. As is evident from these illustrations, the last cyema borders very closely 

 upon the cylindrical in form. 



The word "stunting," as here used, also implies a disproportion in normal 

 form, not merely a reduction in size of the entire specimen. Hence none of the 

 stunted specimens are merely undersized, normally proportioned fetuses; for 

 although an equal, universal retardation in growth is conceivable, it is unlikely 

 that such a thing really occurs. Such an assumption would imply that all organs 

 and tissues are equally resistant to interference with the blood or nutritive supply, 

 or to toxins or other influences. It may seem strange, indeed, that no fetuses 

 beyond the length of 20 mm. are included in this group. This fact would seem to 

 imply either that the causes productive of stunting which may be operative up to 

 this time cease to be effective later, or that portions of the cyema have become so 

 resistant that they can no longer become affected in such a way as to- produce 

 stunting. It has long been recognized, however, that stunting of an organism can 

 occur as the result of various influences at any time throughout its period of 

 growth in post-natal life. Hence an assumed increase in resistance of the tissues 

 sufficient to withstand all influences affecting such young fetuses as those here 

 concerned can hardly be offered in explanation for the absence of stunted fetuses 

 among those more than 20 mm. long. Nor can one assume that the causes opera- 

 tive until this stage is reached, or at some particular time before this stage of 

 development has been reached, always come into abeyance when a fetal length of 

 20 mm. has been attained. 



If, on the other hand, we assume that the various tissues or organs are affected 

 only during a transitional sensitive period, perhaps in certain formative stages, 

 we are in conflict with the facts; for upon this assumption we should be able to 

 group the stunted fetuses by the effects produced upon their tissues, organs, or 

 systems of organs even, but this does not seem possible. Nor are the organs 

 affected serially in the order of their development; for, entirely aside from certain 

 things to be discussed in a subsequent chapter, some changes present within these 

 stunted cyemata are quite universal and comparable, no matter at what stage com- 

 plete inhibition of further development has occurred. Moreover, what impresses 

 one most is not the striking modifications of external form, pronounced as these 

 at times are, but the marked structural changes within the organs themselves. 

 To what extent these changes may be attributed to maceration with consequent 

 disintegration, or to dissociated or uncorrelated growth, and whether or not true 

 stunting can be simulated by the effects of maceration alone, will be considered 

 more fully in a succeeding chapter. The explanation for the absence of stunted 

 fetuses beyond a length of 20 mm. is not only the failure to recognize stunting 

 in them, but that maceration changes often become so pronounced that they 

 mask the changes which have been characterized as stunting. When such is the 

 case the specimen is placed in the next group. 



Although gradual death of cyemata or of entire conceptuses in consequence 

 of interference with the source of nutrition has not as yet been established, such a 

 phenomenon is not only possible but highly probable. Death of the cyema or of the 



