154 ORIGIN AND NATURE OF LIFE 



of this analogy. The solvent action is not 

 one of complete passage to the crystalloidal 

 form, for the amount of alkali necessary to 

 give a clear peptized solution is only a small 

 percentage of the calculated amount for 

 neutralizing all the silicic acid into mono- 

 molecules. The solution of the gelatinized 

 mass is due to a partial disruption only, with 

 formation of smaller colloidal complexes. 

 Each of these complexes is held in solution 

 by one or more active crystalloidal molecules 

 of the alkali, the two components so forming 

 what is now termed a crystallo-colloid. 

 Such crystallo-colloids play a most important 

 part in the life-work of the living cells. 

 Proteins have hitherto been spoken of in this 

 volume as if they were wholly organic, but it 

 has long been known that proteins as they 

 occur naturally can never be obtained without 

 an appreciable amount of inorganic matter. 

 This inorganic matter, chemists for long 

 agreed to regard as an impurity, and so it was 

 called " protein ash." It varies from a half 

 to two per cent, in the majority of proteins, 

 and was invariably regarded as a nuisance 

 by earlier physiological chemists, who were 

 striving after pure products of constant 

 composition. It did not fit in with their 

 scheme of things. Modern research has, 



