THE MANIFESTATIONS OF LIFE 85 



steps pass through an enormous series of transformation 

 products so rapidly, that they cannot be followed. 



Indeed, if we start with a relatively stable protein, like 

 egg-albumen, and endeavor to resolve it into less and 

 less complex compounds, we still find ourselves working 

 with a complexity yielding many series of compounds 

 until we are lost in an impenetrable physiologico-chemi- 

 cal labyrinth, beset on every side with a polysyllabic 

 nomenclature that only increases our bewilderment. 



We cannot, therefore, in the present state of knowl- 

 edge pretend to follow the elaborate synthesis of living 

 matter. We can, however, analyze that matter and 

 discover the elementary substances of which it is com- 

 posed, and this has been done again and again with 

 interesting and important results. 



Thus a chemical analysis of cells shows them, without 

 exception, to be composed of C, O, H, N, S, P, K, Ca, Mg, 

 and Fe. 



It must not be supposed that the elements mentioned 

 comprise the full list of all that may be found in either 

 vegetable or animal tissues; instead they form the indis- 

 pensable list to which others may be or commonly are 

 added with advantageous results to the particular organ- 

 isms. Thus, for example, Si is not enumerated, yet it is 

 frequently present in plants and of benefit by increasing 

 the rigidity of the tissues. 



If living substances, either animal or vegetable, re- 

 quire at least ten elementary substances for the elabora- 

 tion of their tissues, it is evident that they cannot per- 

 form their vital functions when the supply of these 

 elements fails. 



It is also evident that no substance can be so well 

 adapted for the supply of the essential elements, in the 

 most useful combinations, as living substance itself, which 

 explains why living beings of the highest kind so uni- 

 versally live upon living things of lower kinds. The 

 next most useful material would be that which had 

 been living, but is in process of dissolution into similar 

 compounds of still assimilable quality. 



