ii6 The Science of Life. 



tated the assumption of a complex organization. In 

 his classic work, entitled Die Elementarorganismen 



(1861), Briicke first clearly contended for 

 ofu c it?ma?e the necessity of this conception. "We 

 vitai^ organ- mus t ", he said, " ascribe to living cells, in 



addition to the molecular structure of the 

 organic compounds which they contain, still another, 

 and otherwise complicated, structure; and this is what 

 we designate by the term organization." "We must 

 always see in a cell a little animal body." The neces- 

 sity of the assumption is simply that we cannot conceive 

 of function apart from structure, and that the structure 

 must be more than that of chemical complexity is shown 

 by the perennial marvel of the chick developing from 

 the egg. "The species ", Nageli said in 1860, " is con- 

 tained in the egg of the hen as completely as in the hen, 

 and the hen's egg differs from the frog's egg just as 

 widely as the hen from the frog." All through the Vic- 

 torian era there has been a succession of theories and 

 phrases as to ultimate vital organization, the "physio- 

 logical units" of Spencer, the "gemmules" of Darwin, 

 the "micellae" of Nageli, the " plastidules " of Haeckel 

 and Elsberg, the "inotagmata" of Engelmann, the 

 "pangens" of De Vries, the "plasomes" of Wiesner, 

 the "idioblasts" of Hertwig, the "biophores" of Weis- 

 mann, and the " idiosomes " of Whitman. There is 

 no clearer expositor of the conception than Whitman, 

 from one of whose essays the quotations in this para- 

 graph have been borrowed. " Development, no less 

 than other vital phenomena, is a function of organiza- 

 tion." "A certain grade of organization is the result 

 of heredity." " Organic unity depends on intrinsic pro- 

 perties no less than does molecular unity." " Organiza- 

 tion precedes cell-formation, and regulates it." He looks 

 forward to finding "the secret of organization, growth, 

 development, not in cell-formation, but in the ultimate 

 elements of living matter or 'idiosomes'." "What 

 these idiosomes are, and how they determine organiza- 

 tion, form, and differentiation, is the problem of pro- 

 blems on which we must wait for more light. All 

 growth, assimilation, reproduction, and regeneration 



