•PHYSIOLOGICAL UNITS' 83 



been found to possess, and its presence in the cell may lead to the 

 following results : — " Molecular agitation results from decomposi- 

 tion of each phosphorised molecule : shocks are continually pro- 

 pagated around. From the chromatin, units of which are thus 

 ever falling into stabler states, there are ever being diffused waves 

 of molecular motion, setting up molecular changes in the cytoplasm. 

 The chromatin stands towards the other contents of the cell in the 

 same relation that a nerve-element stands to any element of an 

 organism which it excites." The distribution of the chromatin so 

 as to form a diffuse network of granules during the growing stage 

 of the cells is in a measure explained on this hypothesis, though 

 from the point of view of the inheritance theory it would seem to 

 be useless. This, among other facts harmonious with his suggestion 

 is pointed out by Spencer when he says : — " During the interval 

 between cell-fissions, when growth and the usual cell-activities are 

 being carried on, the chromatin is dispersed throughout the nucleus 

 into an irregular network ; thus greatly increasing the surface of 

 contact between its substance and the substance in which it is 

 embedded. As has been remarked, this wide distribution favours 

 metabolism." So that, as he remarks, when contemplated from the 

 suggested point of view karyokinesis as it occurs in the cells of 

 almost all tissues is not wholly incomprehensible : " For if the 

 chromatin yields the energy which initiates changes throughout 

 the rest of the cell, we may see why there eventually arises a 

 process for exact halving of the chromatin in a mother cell between 

 two daughter cells." ' The consequences of an unequal division in 

 cells generally are then pointed out, and also the fact that the fore- 

 going interpretation does not attempt to explain the special process 

 known as karyokinesis : the argument implies merely that the 

 tendency of Evolution is to establish some mode for the equal 

 division of the chromatin. 



An important fact is referred to by Verworn ' which tends to 

 support H. Spencer's view as to the stimulating functions of the 

 nucleus. He calls attention to the existence in some cells of com- 



' This view as to the functions of the nucleus seems capable of explaining the 

 facts previously mentioned concerning sections of cells, and the regeneration only 

 of those parts in which the nucleus was contained (p. 40) ; and also the results of 

 Balbiani's experiments with Stentor, showing that the presence of only a sma 1 

 portion of the nucleus in a section of this organism was sufficient to admit of its 

 complete regeneration (p. 41), leading le Dantec to the conclusion that it seemed 

 to act like a chemical compound rather than as an organ. 



" " General Physiology," Transln. 1899, p. 89. 



