272 TRANSACTIONS OF THH CANADIAN INSTITUTE. [VOL. I. 



That the nucleus is the seat of formative energy is shown by a number 

 of observations*, especially those which bear on the vegetable cell. In 

 the latter the first stages, at least of starch formation, are carried out in 

 the nucleus and this secretes a compound which is finally converted by the 

 the cytoplasm into starch. Korscheltf has also determined that in the 

 formation of the chitinous processes on the eggs of Nepa and Ranatra 

 the chitin necessary for each process is elaborated in a cavity between 

 and surrounded by two epithelial nuclei, and the only legitimate conclu- 

 sion from such a circumstance is that the chitin is derived from a nuclear 

 substance. I may also here refer to the fact that my own observations 

 have definitely shown that the haemaglobin of the red corpuscles in 

 Necturus and Ai)iblystoma is derived from the chromatin of the nucleus 

 both of the fully formed as well as of the developing red cell, and that the 

 haemaglobin so formed diffuses through the nuclear membrane and be- 

 comes fixed in the cytoplasm. All these facts point definitely to the 

 prominent part played by the nucleus and if everything in connection 

 therewith is carefully studied, it will be admitted, I believe, that the inter- 

 pretation which I have given of the changes occurring in the nuclei of the 

 pancreatic cell during the various phases of glandular activity, is not a 

 strained or a far-fetched one. 



APPENDIX. 



After the foregoing was written, a paper containing the observations 

 of Eberth:|; on the pancreatic nebenkerne in salamander came into my 

 hands. In this is advanced a new view of the relations of these bodies, 

 or pseudo-nuclei, as Eberth prefers to call them. He states that they 

 are developed out of the reticular fibrillje of the cytoplasm, the latter at 

 spots apparently becoming swollen, or thickened by fusion with their 

 neighbors, and at the same time altered in composition, whereby their 



* See a resume of such researches in Strasburger : " Ueber Kern-und Zelltheilung im Pflan- 

 zenreiche nebst emem Anhang iiber Be fruchtung," Jena, 1888, pp. 194-204. 



t" Ueber einige interessante Vorgange bei der Bildungder Insecteneier." Zeit. liir wess. Zool. 

 Ed. 45- 



JNeber Einschliisse in Epithelzellen. Fortschritte der Medicin, Sept. i,, 1890. 



