286 JORDAN. [Vol. VIII. 



egg substance, and his embryogenic cell lying at the bottom 

 of this canal. He regards the external origin of this body 

 as streno-thening his view of a fundamental difference between 

 it and the germinal vesicle and as an additional reason for 

 insisting on the separation of the nutritive and germinative 

 elements of the ovum. Balbiani does not agree with v. Bam- 

 beke that the embryogenic cell disappears before the ^gg 

 reaches maturity, but holds that it persists even after fer- 

 tilization. 



In a later paper Balbiani ('83) brings forward some new 

 observations, which, if confirmed, are certainly important. 

 He finds that the eggs of GeopJiilus, when treated with dilute 

 acetic acid show a process of the germinal vesicle which pro- 

 jects into the body of the egg. There are sometimes several 

 of these processes, each process consisting of a double tube, 

 the outer tube communicating with the nucleus, the inner 

 with the nucleolus. The "vitellin protoplasm" at the outer 

 extremity of these tubes becomes denser, and presumably 

 receives substances through the tubes from the nucleus and 

 nucleolus, and this vitelline protoplasm so comes to contain 

 "tous les elements d'une cellule" ! These "corps intra- 

 vitellins" then break away — though this part of the process 

 was not directly observed — and can thereafter be recognized 

 as true " noyaux vitellins." These " noyaux vitellins," ac- 

 cording to Balbiani, now become follicle cells ! Whether 

 Balbiani's views have undergone any further modification 

 since the appearance of this last paper I have no means of 

 knowing, but must confess to some bewilderment at the 

 kaleidoscopic comprehensiveness of the views just stated. 



Schutz ('82) at about this time published a brief account of 

 his work upon the Dotterkern — principally in Arachnids — 

 and after summing up the work of previous investigators con- 

 cludes that the Dotterkern has a nutritive significance. Schutz, 

 however, appears to have overlooked what was in many respects 

 the soundest utterance on the amphibian Dotterkern. O. Hert- 

 wig ('77) observed the Dotterkern in the eggs of Rana, and con- 

 cluded that very great morphological significance could not be 

 attributed to it since it was not found in all amphibian ova. 



