The Process of Life. 33 



frequently the products of explosive activity are made use 

 of. In the case of bone-cells, one of the products of 

 disruption is of permanent use to the organism, and 

 constitutes the solid framework of the skeleton. In the 

 case of the secreting cells of the salivary and other diges- 

 tive glands, one of the disruptive products is of temporary 

 value for the preparation of the food. It is exceedingly 

 probable that these useful products of disruption, perma- 

 nent or temporary, took their origin in waste products for 

 which natural selection has found a use, and which have 

 been, through natural selection, rendered more and more 

 efficacious. This, however, is a question we are not at 

 present in a position to discuss. 



In the busy hive of cells which constitutes what we 

 call the animal body, there is thus ceaseless activity. 

 During periods of apparent rest the protogen filaments 

 of the cell -net are engaged in constructive work, building 

 up fresh supplies of complex and unstable materials, 

 which, during periods of apparent activity, break up into 

 simpler and more stable substances, some of which are 

 useful to the organism while others must be got rid 

 of as soon as possibleu From another point of view, the 

 cells during apparent rest are storing up energy which 

 is utilized by the organism during its periods of activity. 

 The storing up of available energy may be likened to the 

 winding up of a watch or clock ; it is during apparent rest 

 that the cell is winding itself up ; and thus we have the 

 apparent paradox that the cell is most active and doing 

 most work when it is at rest. During the repose of an 

 organ, in fact, the cells are busily working in preparation 

 for the manifestation of energetic action that is to follow. 

 Just as the brilliant display of intellectual activity in a 

 great orator is the result of the silent work of a lifetime, 

 so is the physical manifestation of muscular power the 

 result of the silent preparatory work of the muscle-cells.* 



One point to be specially noted is the varied activity 



* I do not mean, of course, to imply that there is no reconstruction during 

 activity, but that it is then distinctly outbalanced by disruptive changes. 



D 



