THE ULTIMATE SELF-ELEMENTS 



83 



become more than ever inseparable. All the facts of structure on the 

 one hand and of function on the other have both to be interpreted in 

 terms of the constructive and disruptive changes in the living matter 

 itself. The general theory may be summarized in the accompanying 

 diagram. Protoplasm is regarded as an exceedingly complex and 

 unstable compound, undergoing continual molecular change or meta- 

 bolism. On the one hand, more or less simple dead matter or food 

 passes into life by a series of assimilative ascending changes, with each 

 of which it becomes molecularly more complex and unstable. On 

 the other hand, the resulting protoplasm is continually breaking down 

 into more and more simple compounds, and finally into waste pro- 

 ducts. The ascending, synthetic, constructive series of changes are 



Fig. 21. — Protospongia, a colonial infusorian, showing the difference 

 heiween outer and inner cells. — From Saville Kent. 



termed "anabolic " ; and the descending, disruptive series, " katabolic." 

 Both processes may be manifold ; and the predominance of a partic- 

 ular series of anabolic or katabolic changes implies the specialization 

 of the cell. The upper figure (a) represents the complex unstable 

 protoplasm as if occupying the summit of a double flight of steps ; 

 it is formed up the anabolic steps, it breaks up and descends by the 

 katabolic. The lower figure (b) is a projection of the other, its con- 

 vergent and divergent lines serving to represent the various special 

 lines of anabolism and katabolism respectively, and the definite com- 

 ponent substances ("anastates" and "katastates") which it is the task 

 of the chemical physiologist to isolate and interpret (see pp, 114-7). 



