THEORY OF THE DEVELOPMENT OF ORGANISMS 113 



the functions of its life is limited by these others and 

 by the whole. The further this is carried the more 

 the cell falls short of its independence as an 

 elementary organism, and appears only as a part 

 with its functions subordinate and in dependence 

 upon the whole. 1 



Although from the point of view of morphology 

 it has become more and more imperative to regard 

 the cell as the unit of the higher organism, still, 

 from the physiological point of view the higher 

 organisms must be regarded as masses of material 

 acting as wholes, and composed of several grades 

 of structural parts, subordinate in function to the 

 whole, and displaying only a limited division of 

 capacities. And so the cell theory, according to 

 which the cell was exalted unduly as the unit of life, 



1 The assumption of doubling division does not involve the 

 assumption that the germinal mass is unalterable. Although I do 

 not regard the process of division as a mechanism for breaking up 

 the idioplasm into dissimilar groups of determinants, I regard the 

 idioplasm and here I agree with Naegeli as only relatively stable. 

 In course of time external and internal forces may slowly alter it. 

 On the one hand, the idioplasm of the reproductive cells in the 

 course of generations may slowly alter, while, on the other hand, 

 the idioplasm of cell groups in an organism may acquire a local 

 character in correspondence with their different topographical and 

 functional positions in the whole creature, and in relation to their 

 place in the organic division of labour, just as in human com- 

 munities individuals become altered by the lifelong exercise of some 

 calling. 



Nor does the doctrine of doubling divisions conflict with those 

 conclusions of pathology according to which, in the process of 

 regeneration, cells and tissues give rise only to cells and tissues of 

 their own order. For further details see my treatise, Ei und 

 Samen-Bildung lei Nematoden, pp. 97-99. These slight sugges- 

 tions are only to prevent misconceptions. 



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