414 Observations on Organic (Jiemistry 



changeable theoretical notions, — for the theory of volumes, for instance. 

 And when instead of the obscure notion concerning the saturating pow- 

 er of the acids which then prevailed, I endeavoured to give a better one, 

 according to my own apprehensions, and when I attempted to apply an 

 indisputable axiom of mechanics to the phenomena of combination and 

 decomposition, in what respect did I justly incur reproach ? Upon phe- 

 nomena imperfectly studied before I commenced, and upon new obser- 

 vations, I have based and established the theory of putrefaction and 

 decay ; I have shown that humus cannot be the source of the carbon of 

 vegetables ; I have, in the course of my investigations into the trans- 

 formations which nitrogenous substances undergo in the presence of 

 water and air, found ammonia to be the ultimate and only source of 

 nitrogen in plants ; and I have determined the necessity of the alkalies, 

 the alkaline earths, and the phosphates, to vegetable life, which was so 

 long disregarded by chemists and mistaken by physiologists. 



What connection is there between these views, which are opposed to 

 those of Berzelius, and my other labours ? Why does my method of 

 purifying antimony no longer, according to his account, yield antimo- 

 ny free from arsenic ? Why is my method of preparing cyanide of po- 

 tassium fraught with difficulties now, and no longer to be considered an 

 improvement? Why does my separation of nickel from cobalt now 

 exist only upon paper? Why does Berzilius incessantly warn us, in 

 physiological investigations, not to go beyond his labours of thirty years 

 since? Shall we then continue to consider blood corpuscules as globulin, 

 and caseine as soluble in water ? — albumen as an acid and a base ? Or 

 to assume a dozen substances as constituents of the bile, when our in- 

 vestigations have proved these things to be otherwise? 



Shall we continue to bruise the liver and kidneys in a mortar in or- 

 der to obtain a knowledge of their composition and vital functions ? Of 

 what avail have all these labours proved to physiology ? Their results 

 drag heavily along, in the Manuals, a cumbrous and useless burthen ; 

 they introduced totally fallacious methods of investigation into chemical 

 physiology, and created that aversion and nausea with which physiolo- 

 gists have regarded chemistry. What light could such investigations, 

 made after the example of Fourcroy and Vauquelin, throw upon the 

 mysterious processes of organic life ? What advantage could possibly be 

 derived from all these figures which were unconnected with questions 

 of fact, from investigations made without any definite object, and con- 

 ducted without method? Whilst, with the analysis of a silicate, the 

 ultimate problem of the analyst was solved, the mere production of the 

 animal constituents, and their analysis must be considered only as the 



