RELATIONS BETWEEN THE NUCLEUS AND CYTOPLASM A 55 



has of late acquired a fictitious importance, probably quite disproportionate 

 to its real functional value 1 , owing to the peculiar and interesting formative 

 changes which have been found to take place in it. The decreased, or 

 even subordinate importance, commonly attributed to the nucleus subse- 

 quently to the discovery of centrosomes 2 , is another example of how our 

 judgement of the functional importance of an organ is influenced by our 

 knowledge of that part of its structure which is visible to us. It is not 

 impossible that there would be no lack of theories put forward ascribing to 

 the cytoplasm predominant importance, if only the remarkable structural 

 peculiarities, which it certainly possesses, were actually visible. However 

 important and interesting the relatively large size of the nucleus in 

 embryonic cells may be ; this does not afford any conclusive evidence one 

 way or the other 3 . Size is not all-important. The value of an individual 

 to society is hardly at all dependent upon his stature, and indeed, minute- 

 ness may endow an organism with great powers. Thus, Bacteria afford 

 a good example of how, owing to their enormous powers of propagation, 

 tiny living organisms are able to produce the most extraordinary results 

 and even to destroy the largest and most highly specialized beings. More- 

 over, it must be remembered that in fertilization the male and female 

 elements probably mutually stimulate each other, and the most minute 

 quantity of a stimulating substance may induce very marked and far- 

 reaching changes. 



The result of the division of labour which has taken place in the 

 protoplast is that in certain functions the nucleus, in others the cytoplasm, 

 plays the principal part. For the perfect performance of any function, 

 however, mutual co-operation is necessary ; for there can be no doubt but 

 that in every instance each influences and stimulates the other. Even 

 though the nucleus were especially concerned in emitting stimulating 

 impulses, and were in certain cases even comparable with a central nervous 

 system, the above considerations would nevertheless be in no wise vitiated. 

 It is only natural and to be expected that formative changes should be 

 markedly influenced by the nucleus. The action of a stimulus affecting 

 the nucleus and cytoplast, such as that which gives rise, for example, to 

 a formation of galls, will be modified and largely determined by the nature 

 and character of the growing tissues affected. Hence, galls formed by the 



1 See also Verworn, Allgemeine Physiologic, 1895, p. 486. 



2 For literature on Centrosomes, see p. 40. Also O. Hertwig, Zelle, 1893, pp. 47-146 ; Haackc, 

 Biol. Centralbl., 1895, Bd. xiv, p. 44; Boveri, Zur Physiologic der Kern- und Zelltheilung, 1897 ; 

 Strasburger, Jahrb. f. wiss. Hot., 1897, Bd. Ill, p. 387. [The aggregation of the nuclear chromatin 

 into a definite number of chromatin filaments appears to be merely a sign of great nuclear activity, 

 and is not characteristic of mitosis only, for it may be seen in actively secreting gland-cells (Huie, 

 1. c., later).] 



8 On changes of size in the nucleus, see Fr. Schvvarz, Cohn's Beitrage zur Biologic, 1892, Bd. v, 

 p. 80 ; Zacharias, Flora, 1895, Krganzungsband, p. 217. 



