ON THE PHYSICAL BASIS OF LIFE 105 



also, in strictness, true that we know nothing about the 

 composition of any body whatever, as it is. The state- 

 ment that a crystal of calc-spar consists of carbonate of 

 lime, is quite true, if we only mean that, by appropriate 

 processes, it may be resolved into carbonic acid and 

 quicklime. If you pass the same carbonic acid over the 

 very quicklime thus obtained, you will obtain carbonate 

 of lime again ; but it will not be calc-spar, nor anything 

 like it. Can it, therefore, be said that chemical analysis 

 teaches nothing about the chemical composition of 

 calc-spar ? Such a statement would be absurd ; but it is 

 hardly more so than the talk one occasionally hears 

 about the uselessness of applying the results of chemical 

 analysis to the -living bodies which have yielded them. 



One fact, at any rate, is out of reach of such refine- 

 ments, and this is, that all the forms of protoplasm 

 which have yet been examined contain the four ele- 

 ments, carbon, hydrogen, oxygen, and nitrogen, in very 

 complex union, and that they behave similarly towards 

 several reagents. To this complex combination, the 

 nature of which has never been determined with exact- 

 ness, the name of Protein has been applied. And if we 

 use this term with such caution as may properly arise 

 out of our comparative ignorance of the things for which 

 it stands, it may be truly said, that all protoplasm is 

 proteinaceous, or, as the white, or albumen, of an egg 

 is one of the commonest examples of a nearly pure 

 proteine matter, we may say that all living matter is 

 more or less albuminoid. 



Perhaps it would not yet be safe to say that all forms 

 of protoplasm are affected by the direct action of 

 electric shocks ; and yet the number of cases in which 

 the contraction of protoplasm is shown to be affected 

 by this agency increases every day. 



