430 Observations on Organic Chemistry 



not had the remotest intention of undertaking the explanation of any 

 really vital phenomenon upon chemical principles. The only part 

 which chemistry now and for the future can take in the explanation of 

 the vital processes is limited to a more precise designation of the phe- 

 nomena, and to the task of controlling the correctness of inferences, and 

 ensuring the accuracy of all observations by number and weight. 



The term hydrogen, for example, designates for every body a sub- 

 stance which is one of the constituents of water, but for the chemist the 

 meaning of the term is far more comprehensive ; it embraces an aggre- 

 gation of properties ; joined with other words, such as chlorine, oxygen, 

 sulphur, nitrogen, &c, it presents to him a volume filled with thoughts 

 and conceptions, and brings innumerable phenomena before his eye. 

 The same may be said of a chemical formula, which is far more to the 

 chemist than the expression of the results of an analysis ; it renders 

 intelligible to him. the formation of the substance it designates, the 

 products of its decomposition, together with the relations which it bears 

 to other substances. Thus, by simply placing together the formulae 

 of alchol, of acetic acid, and of acetone, all the alterations and decom- 

 positions which attended the formation of acetic acid become at once 

 perceptible. Without this method of designating chemical compounds 

 no just apprehension of them is possible. 



The physiologist, in his own way, has created for himself certain 

 conceptions of bile, saliva, cerebral substance, albumen, uric acid, &c. in- 

 cluding the physical properties of these substances, their colour, consis- 

 tence, taste, &c, which he has ascertained, together with the relations 

 he has observed them to bear to the organism and to its individual 

 parts. But this physiological conception does not embrace all their pro- 

 perties and relations. In the hands of the chemist these organic matters 

 manifest innumerable peculiarities in their relation to other substances, 

 such as the raptitude to form combinations, to undergo decompositions ; 

 moreover, the knowledge of their elements, their invariable, composition, 

 in short, all their chemical characters, belong to the word bile, albumen, 

 &c, for the chemist. It must be perfectly obvious that the placing to- 

 gether of the words in the physiological sense can give us no information 

 of their true import, their chemical meaning must form a part of their 

 definition, if we are to comprehend all the points connected with them. 



In the compound atoms of which the animal organism consists we 

 observe the same fixed and immutable proportion as in inorganic nature. 

 The laws of their chemical composition are as true for organic as for 

 mineral substances. They ought not, and cannot, be disregarded by 

 the true student of nature. 



