OF LIVING MATTER 41 



This rather large trumpet-shaped Ciliate possesses a long, monili- 

 form nucleus, and Balbiani ' carefully studied the question as to 

 the amount of this nucleus existing in a fragment of the organism 

 which would suffice, in order that regeneration of the form and 

 structure of the organism from such a fragment might occur. The 

 account given of these experiments is as follows : — 



"A Stentor having been divided transversely into three seg- 

 ments, an anterior one containing a nuclear chaplet of six grains, 

 one containing only a single grain, and a posterior segment having 

 four grains, by the next day all three were completely regenerated 

 into perfect Stentors ; and though the middle fragment, with its 

 single nuclear grain, had to undergo much more numerous and 

 more profound transformations than the other two, its regeneration 

 had taken place in the same time as that of the others, and it had 

 become just as perfect a Stentor — only smaller, on account of 

 the difference in size of the three segments at the time of 

 section. ... In other analogous experiments the single nuclear 

 grain was contained in the posterior, or in a longitudinal, 

 fragment of the body, and the results have always been similar. 

 We must conclude from these facts that the particular quantity of 

 nuclear substance 'existing is of no importance, either for the 

 degree of perfection or for the progress of the regeneration, and 

 that a single grain of the nucleus behaves in this respect just like 

 an entire nucleus." 



We are warranted in concluding from these experiments, as 

 le Dantec does, that the nucleus seems to act like a chemical 

 substance rather than as an organ, since, as he says, " a portion of 

 the nucleus in a portion of the corresponding protoplasm brings 

 about the same syntheses as an entire nucleus in an entire 

 plastide." This is an important conclusion from the point of view 

 of the functions of the nucleus, and is fairly compatible with the 

 suggestion made by Herbert Spencer ' that having regard to its 

 chemical complexity and relative instability " the nucleus is a 

 source of perpetual molecular disturbance — not a regulating centre 

 but a stimulating centre." Nothing further on this subject need, 

 however, be said for the present. We may now turn from this 

 digression for a few concluding words upon the subject with 

 which we are more immediately concerned, namely, the property of 

 spontaneous fission, as a fundamental characteristic of living matter. 



■ " Ann, de micrographie," 1892 and 1893. 



' " Principles of Biology," Revisd, Edn., 1898, Vol. I, p. 260. 



