14 



G. CARL HUBER 



Ovulation may have occurred so late that the spermatozoa 

 may have died before the ova reached the ampullar portion of 

 the oviduct. This explanation, it would seem, is invalidated 

 by the fact that the position of the ova in the oviduct, as shown 

 by graphic reconstruction, is essentially the same as in the other 

 four rats studied, and in which fertilized ova were found, so that 

 ovulation must have preceded the killing of the animal by some 

 hours. The other reason, more plausible, attributes non-fertili- 

 zation to a pathologic condition of the genital tract. In this rat, 

 one ovary was distinctly pathologic, with periovarian capsule 

 greatly distended with a sanguinous liquid, while the upper end 

 of the uterine horn with adjacent oviduct on the other side, 

 as seen in sections, presented evidence of inflammation and epithe- 

 lial desquamation, in part occluding the lumen. II seemed 

 evident, therefore, that the spermatozoa introduced in the genital 

 tract were unable to penetrate to the oviduct and consummate 

 fertilization. The other two unfertilized ova, found with ova 

 in the pronuclear stage, were in oviducts in which no spermato- 

 zoa were found. Both in the mouse and the rat, relatively few 

 spermatozoa reach the upper end of the oviduct ; too few, it would 

 seem, to consummate fertilization of all the ova in certain cases. 

 In all of the ova which contained the second maturation spindle, 

 this was in the monaster phase and in tangential position. In 

 size, shape, and chromatin configuration, all presented the char- 

 acteristics described and figured by Sobotta and Burckhard and 

 Kirkham and Burr, therefore, need not be considered further. 



