130 LAY SERMONS, ADDRESSES, AND REVIEWS, [yn 



ment that a crystal of ealc-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 ealc-spar, nor anything 

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

 teaches nothing about the chemical composition of ealc- 

 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 anv 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 elements, 

 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 exactness, 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 ot protoplasm is shown to be effected by this 

 agency increases every day. 



Nor can it be affirmed with perfect confidence, that all 

 forms of protoplasm are liable to undergo that peculiar 

 coagulation at a temperature of 40° — 50° centigrade, 



