which, bake it and paint it as he will, remains clay, sep- 

 arated by artifice, and not by nature, from the common- 

 est brick or sun-dried clod. Thus it becomes clear that 

 all living powers are cognate, and that all living iorms 

 are fundamentally of one character. 



The researches of the chemist have revealed a no less 

 striking uniformity of material composition in living mat- 

 ter. In perfect strictness, it is true that chemical inves- 

 tigation can tell us little or nothing, directly, of the com- 

 position of living matter, inasmuch as such matter must 

 needs die in the act of analysis, and upon this very ob- 

 vious ground, objections, which I confess seem to me to 

 be somewhat frivolous, have been raised to the drawing 

 of any conclusions whatever respecting the composition 

 of actually living matter from that of the dead matter 

 of life, which alone is accessible to us. But objectors 

 of this class do not seem to reflect that it is also, in strict- 

 ness, true that we know nothing about the composition 

 of any body whatever, as it is. The statement that a 

 crystal of calc-spar consists of carbonate of lime, is 

 quite true, it 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 quick- 

 lime 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 useless- 

 ness of applying the results of chemical analysis to the 

 living bodies which have yielded them. One fact, at 



