Ryder.] LD& [May 16, 



accumulated products of assimilation in order to avoid the peripheral ob 

 struction of respiration the same argument can be applied to the localiza- 

 tion of the germinal matter at the posterior pole. Suppose an ancestral 

 Volvocine form still in a condition when it had not yet began to perma- 

 nently cohere into a spherical colony. Suppose further, that when its 

 maximum dimensions of growth had been nearly attained all its cells were 

 so nearly alike that the differences woulcl be extremely slight between 

 them. But suppose them to be even very slightly different enough in size 

 to respond to an equilibration of the colony by gravity at the surface of a 

 still pool on a quiet sunny day. The upper cells would undoubtedly be 

 stimulated into a slightly greater assimilative activity than the lower ones 

 away from the light and shaded by the upper ones. The assimilated ma- 

 terials would not only be repelled towards the lower pole by this 

 activity of the protoplasm of the upper pole, but would actually gravitate 

 towards that pole. We thus see that, analyze the physiological data in 

 whatever manner we please, there finally remains no warrant for the hypo- 

 thesis that the germ-plasma is set aside in special cells for the express ob- 

 ject of maintaining the continuity of the processes of reproduction. This 

 apparent setting aside of germinal matter is itself the consequence of the 

 necessary mode of the correlated action of physical agencies, ending in 

 cumulative integration through continuous growth, and is clearly not the 

 result of any elaborate selective process. 



The running down katabolically of some of the assimilated or stored 

 germinal matter is proof of its loss of function and uselessness to the par- 

 ent organism except in so far as such cells are a repository for such ma- 

 terials. There is therefore no conclusion open to us but that one which 

 assumes that the motive force of all these elaborate correlations in such a 

 simple multiceliular organism * are the results of the indirect action under 

 cosmical conditions, of the principle that living matter tends to increase 

 in bulk beyond the actual physiological requirements of its secular exis- 

 tence. 



SUMMARY OF CONCLUSIONS. 



1. Cumulative integration or assimilation beyond the current needs of 

 the parent organism seems to have arisen as a consequence of the physical 

 properties of "living" matter, as manifested in metabolism or the char- 

 acteristic continuous disintegration and integration of such matter. It is 

 a property of "living" matter which is a consequence of its molecular 

 constitution; if so, "living" and the continuity of molecular change 

 through metabolism is a physical process, differing only from ordinary 

 chemical processes in its complexity, continuity and capability of self- 

 maintenance under certain conditions ; its most important consequence is 

 continuous growth. 



*The researches of Overton and myself Ijave proved beyond doubt that Volvox is not 

 a protozoon or protophyte as erroneously supposed by Lankester and Butschli. 



