Physiology and Biology of the. Protozoa. 487 



cell-individual as perfectly congruent in structure and func- 

 tion. Moreover, in most multinucleate Protozoa the nuclei 

 appear to the observer congruent in structure, for there 

 are generally no data from which to demonstrate any diffe- 

 rences. For this reason it was interesting to me to find in 

 the two nuclei of Amoeba hinucleata an object which may be 

 investigated from this point of view. As I pointed out in 

 my description of this remarkable Amoeha^, the nuclei, two 

 of which are present, are very large, and are distinguished 

 by a very variable form and arrangement of the chromatic 

 substance, and it appears that the two nuclei of the same 

 Amoeba always agree in this respect (fig. 13). For example, 

 if the chromatin is distributed in the nuclear fluid in larger 

 and smaller fragments, this is the case in both nuclei (a) ; if it 

 is broken up into a finely granular mass (5), if there is a central 

 nucleolus-like lump in the nucleus (c), or if the chromatic 

 substance is deposited towards one side (c?), the two nuclei 

 always agree with each other. Here^ therefore, we can defi- 

 nitely prove the congruence of tlie nuclei ; and I believe that it 

 also furnishes a proof that the chromatin in the nucleus is an 

 important factor , that something depends upon the hind of its 

 substance, and roe have not to do with a mere accumidation of 



• • • 7 



nutritive materiat. 



It still remains for me to say something about the part 

 which the subsidiary nucleus has to play in the regenerative 

 processes ; but I am unfortunately not in a position to say 

 anything positive about it. 



Until quite recently nothing was known of sidtsidiary 

 nuclei in Stentor, and only Maupas t has made any state- 

 ments regarding them, in which he describes the ^ibsidiary 

 nuclei as separate granules irregularly distributed, one or 

 more of which lie in the neighbourhood of each joint of the 

 nucleus. 



Balbiani did not succeed in confirming Maupas's observa- 

 tion, but I have repeatedly been able to convince myself of 

 its correctness. Very frequently, although not always, my 

 preparations showed, coloured red with carmine, corpuscles 

 agreeing with those described by Maupas, as I could perceive 



multinucleate. Ne\'ertheless the fusion and subsequent reseparation into 

 numerous nuclei might have already taken place before the commence- 

 ment of division became visible on the body of the Infusorian, just as I 

 have described in the case of Oxyti-icha scutellum (Gruber, " Ueber Kern 

 und Kerutheilung bei den Protozoeu," in Zeitschr. f. wiss. Zool. Bd. xl.). 



* " Studien iiber Anioben," &c. 



t Maupas, " Contributions a I'^tude morphologique et anatomique des 

 lufusoires ciliees," in Arch, de Zool. Exp. et Gen. s(5r. 2, tome i. pp. 652 

 et seqq. 



