THE INADEQUACY OF THE CELL-THEORY. 123 



advantage in the pelagic fish-egg, but still better in the Toad- 

 fish-egg. It is needless to cite further examples of this sort, 

 for the embryology of every animal is full of them, and no one 

 can fail to find who looks for them. 



If the formative processes cannot be referred to cell-division, 

 to what can they be referred ? To cellular interaction ? That 

 would only be offering a misleading name for what we cannot 

 explain ; and such an answer is not simply worthless, but posi- 

 tively mischievous, if it put us on the wrong track. Loeb's 

 experiments in heterogenesis furnish a refutation of the inter- 

 action theory. The answer to our question may be difficult to 

 find, but we may be quite certain that when found it will recog- 

 nize the regenerative and formative power as one and the same 

 thing throughout the organic world. It will find, as Wiesner 

 has so well insisted, a common basis for every grade of organi- 

 zation, and it will abolish those fictitious distinctions we are 

 accustomed to make between the formative processes of the 

 unicellular and multicellular organisms. It will find the secret 

 of organization, growth, development, not in cell-formation, but 

 in those ultimate elements of living matter, for which idiosomes 

 seems to me an appropriate name. 



What these idiosomes are, and how they determine organi- 

 zation, form, and differentiation, is the problem of problems 

 on which we must wait for more light. All growth, assimi- 

 lation, reproduction, and regeneration may be supposed to have 

 their, seat in these fundamental elements. They make up all 

 living matter, are the bearers of heredity, and the real builders 

 of the organism. Their action and control are not limited by 

 cell-boundaries. As Heitzmann and others have long insisted, 

 the continuity of these elements is not broken by cell-walls. 

 The organization of the egg is carried forward to the adult as 

 an unbroken physiological unity, or individuality, through all 

 modifications and transformations. The remarkable inversions 

 of embryonic material in many eggs, all of which are orderly 

 arranged in advance of cleavage, 1 and the interesting pressure 

 experiments of Driesch by which a new distribution of nuclei 

 is forced upon the egg, without any sensible modification of the 



1 As will be shown later. 



