174 



STUDIES ON PATHOLOGIC OVA. 



field and graph shown in Chart 1, although made upon the basis of selected normal 

 material from the Carnegie Collection, supplemented by data from the literature, 

 probably can not give us anything more than a very rough approximation of a 

 portion of a curve illustrating the relation between cyemic and chorionic size 

 during the first month. 



Among the cases used for this graph there are a few in which the cyemic 

 length is somewhat greater than the greatest chorionic measurement. This may 

 be due to the fact that the chorionic vesicle was measured after it was opened and 

 fixed. It is always diffcult to restore the form of opened chorionic sacs in fluid, 

 even with the greatest care, unless they are coated with blood and decidua so that 

 their walls are stiffened. 



70 



60 



40 



20 



15 



24 



23 



' I 



10 



20 



30 



40 



50 



60 



70 



80 



90 



100 



Greatest dimensions of chorion in millimeters. 



CHART 1. Field and graph showing correlation between cyemic and chorionic size, based on the 255 

 selected normal specimens. Uterine specimens indicated by dots, tubal by circles. 



In some instances conceptuses with different menstrual ages have the same 

 size, a fact which not necessarily finds its explanation in the existence of normal 

 growth differences, but rather in the earlier death of one cyema or conceptus. Other 

 discrepancies between the length of the cyema and the dimensions of the 

 chorionic vesicle may be due to distention of the latter after death of the former, 

 or possibly to actual growth of the chorionic vesicle after the death of the embryo. 

 It is fortunate that we possess a double check on our data, for we can consider 

 the relation of the size of the ovum and the cyema independently, and also can 

 compare each with the menstrual age. 



