Chap, ii.] AJ^OEGANIC AND ORGANIC SUBSTANCES. 13 



animals possess a great inertia and a notable instability ; often 

 they are susceptible of isomeria (sugars, dextrine, and the like). 



As regards the more complex compounds, those in which 

 carbon, hydrogen, azote, sulphur, phosphorus ally themselves to 

 form the substances called albuminoidal, molecular instability is 

 carried iu them to the maximum; the unfoldings, the isomeric 

 modifications are effected with extreme facility. Further on we 

 shall, in reference to nutrition and digestion, signalise the im- 

 portant isomeric modifications which transform the insoluble 

 albuminoidal aliments into soluble substances. Let us call atten- 

 tion also, by the way, to the still more curious and typical 

 metamorphoses which the various kinds of virus and miasma 

 produce ia the a lbuminoidal substances of living bodies. It 

 deserves remark, besides, that these last substances, when once 

 modified isomerically, possess the murderous property of trans- 

 mitting by simple contact to sound organic substances the 

 molecular alteration they have themselves undergone. 



But, finally, we may observe that these actions of contact are 

 not peculiar to organic substances. They have, like the isomeric 

 phenomena, their analogues in the chemistry called anorganicai. 

 In effect there is no radical difference, no abruptly settled 

 frontier between organic chemistry and inorganic chemistry. 

 The two kinds of chemistry study the same elementary bodies 

 which are subject to the same laws. Organic substances proceed 

 from anor ganic substances, and return to them incessantly, to 

 come forth from them anew. For the most part we merely find 

 in organic substances greater complexity and instability. Also 

 we see modem chemistry striving more and more to pluck from 

 living bodies the monopoly of the fabrication of substances called 

 organic. 



Moreover, if we place in a graduated series the mineral and 

 organic compounds, we discover between the two classes transitory 

 groups, f ormiilg a point of union : these are the carburets of 

 hydrogen, the alcohols, the ethers, ternary acids, fat bodies, the syn- 

 thesis of which the chemist is now able to accomplish. Neither is 

 there anything inalienable or special in the composition of organic 



