238 METAMORPHOSIS OF TISSUE. 



laboratory (by R. Buchheim, now of Dorpat, among others) with 

 the view of determining the quantities of alkaline carbonates, tar- 

 trates, citrates, &c., which are necessary to destroy the free acid 

 of the urine, and further to ascertain the quantities of free tartaric 

 or citric acid which must be taken at one time to allow of a portion 

 appearing unchanged in the urine ; but notwithstanding every 

 attention to the quality and quantity of the food taken during 

 equal intervals of time, the bodily exercise, and other physiological 

 relations, these observations have failed in leading us to any sharply 

 denned numerical results. In experiments of this nature, a num- 

 ber of conditions exert an influence, the determination of which is 

 in part beyond the power or the calculation of the experimentalist. 

 If we could succeed in determining these intricate relations, we 

 should, at all events, have a check upon our calculations regarding 

 the mechanical metamorphosis of matter in the animal body, in as 

 far as the one series of experiments shows the amount of the free 

 acid which is excreted by the kidneys from the body within definite 

 periods of time, whilst the other series might enable us to deter- 

 mine, at least approximately, the quantity of alkali in the blood, 

 and consequently also the amount of blood in the animal body. 

 Although these experiments have not hitherto advanced the 

 science of physiology, they promise to yield more certain results to 

 therapeutics. As far as we are aware, the relations subsisting between 

 acids and alkalies or the salts of the vegetable acids, and the re- 

 actions and constitution of the urine and the sweat, have not yet 

 been considered from a physiological point of view. Physiology has 

 not hitherto been sufficiently applied to medicine, whilst the phar- 

 macologist is ever striving to explain the presumed action of the 

 most irrational agents by apparently rational means, and to defend 

 their respective applications. 



With the view of forming some estimate of the oxidising 

 capacity of the animal organism, I formerly turned my attention 

 to the study of the metamorphoses which salicin undergoes in its 

 passage through the body ; arid I formerly inferred from the re- 

 action which the urine exhibits towards the persalts of iron after 

 the use of salicin, as well as from other experiments, that the 

 organism can only so far oxidise saligenin as to lead to the forma- 

 tion of salicylous acid. Stadteler was led to conclude from his 

 experiments on the volatile acids of the urine of the herbivora, that 

 phenylic acid passed into the urine, and that the blue colour 

 imparted to the alcoholic and ethereal extracts of urine, induced by 

 the salts of iron after the use of salicin, depends upon phenylic 



