ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 483 



to the place in the cell which this material with its property of 

 evoking life occupies. Among these the chief are the phenomena of 

 conjugation of Iufusoria, taken in connection with facts recently 

 acquired in the study of the process of fertilization in the Metazoa. 

 The gradually diminishing vital energies of the Infusoria are 

 strengthened afresh by conjugation, and this comes about by a partial 

 or total renewal of the nucleus from the so-called nucleoli or primary 

 nuclei. A total or partial renewal of the nucleus of the ovum is also 

 seen in fertilization, and it is most probably effected by the spermatic 

 nucleus. 



(This passage was written in 1876, when the first and imperfect 

 account of the process of fertilization had just been put forth ; but it 

 would be easy to alter it so as to bring it into accordance with our 

 present knowledge, without interfering with the part played by the 

 nucleus.) 



Thus the failing vital powers of the Infusoria are raised up again 

 by the renewal of the nucleus, and a similar result occurs in the 

 process of fertilization ; is it not, therefore, a justifiable conclusion 

 that the vital ferment which has been spoken of, actually resides in 

 the nucleus of the cell, whenever this is present. It is not the whole 

 nucleus which is to be interpreted in this way, but only a small part 

 of its bulk. Thus in the case of the Infusoria, it must be assumed 

 that the freshly produced life-ferment is collected more especially in 

 the so-called nucleoli, but in higher organisms in the reproductive 

 cells, chiefly in the nucleus of the male reproductive elements." 



N. Cholodkowsky, in discussing * the doctrine of Biitschli, points 

 out certain difficulties in the way of our accepting this view. Some 

 forms, e. g. Hydra, have an asexual as well as a sexual method of 

 reproduction; now, if all the cells of such an animal have the power 

 of producing new individuals they must all be immortal ; yet, as a 

 matter of fact, we know that many die down. It seems to Cholod- 

 kowsky that the cause of the death of the Metazoa is to be sought for 

 in the multicellularity of their organism. A cell has in itself and 

 for itself a potential immortality ; but as soon as differentiated cells 

 are united into an individual there commences amongst them a 

 struggle for existence, which, eo ipso, leads to destruction. The 

 hypothesis of Biitschli recalls the Darwinian doctrine of Pangenesis ; 

 just as Darwin supposed a general distribution of reproductive cells 

 throughout the organism, which only later became concentrated in 

 the generative cells, so does Biitschli deal with his vital ferment, and 

 the doctrine of the latter is therefore only a more physiological way 

 of expressing that of Pangenesis. 



Pelagic and Deep -Sea Fauna, f — T. Fuchs enumerates the 

 distinguishing characteristics of the pelagic and the deep faunas 

 respectively, and makes some inductions as to the reasons for these 

 peculiarities. Pelagic animals are those which are wholly indepen- 

 dent of the shore and the sea-bottom at all stages of their existence. 



* Zool. Anzeig., v. (1882) pp. 264-5. 



t Verh. k. k. Geol. Reichsanstalt, 1882, pp. 49 and 55. Cf. Naturforscher, xv, 

 (1882) pp. 199-202. 



2 K 2 



