ACETIC ACID. 53 



in the animal juices than has now been shown to be the case. On 

 this point there was formerly a controversy between Gmelin and 

 Berzelius ; the former regarding the acid which formed the soluble 

 salts occurring in the animal fluids as acetic acid, while the latter 

 maintained it was lactic acid ; Gmelin's idea was that the volatility 

 of the acetic acid was heightened by its combination with an 

 organic matter. The question has finally been settled in favour of 

 the view maintained by Berzelius. 



I have never been able to recognise it as a normal constituent 

 in any of the animal juices. Scherer has however found it, as I 

 have already mentioned (p. 50), in the juice of flesh, together with 

 other acids of this group. It may often occur in the gastric juice 

 in cases of disordered digestion. In a case where, after vegetables 

 and a little meat, but no vinegar had been taken, the vomited 

 matters were analysed, and I satisfied myself with certainty regarding 

 the presence of acetic acid. It has often been observed by others 

 in vomited matters, but its presence has not always been demon- 

 strated with sufficient chemical accuracy ; for, on the one hand, 

 vinegar or brandy might have been taken previously to the vomiting, 

 or on the other hand, this acid might be confounded with metacetonic 

 or butyric acid. The proof that spirit of wine is converted in the 

 stomach into acetic acid during normal digestion, will be given 

 when we treat of the process of gastric digestion. 



Bouchardat and Sandras* think that they have sometimes dis- 

 covered traces of acetic acid in the blood of animals whose food has 

 been steeped in brandy. 



The answer to the question, what change acetic acid undergoes 

 in the animal organism when conveyed into it from without, 

 belongs to the department of pure physiological chemistry. 



Whether the acids of this group found by Scherer in the fluids 

 of flesh have their origin in the fleshy fibre which has become effete, 

 or whether they arise from the decomposition of other matters, 

 and are only isolated in the muscular juice, are questions which can 

 only be decided by further investigation. 



METACETONIC ACID. C 6 H 5 O 3 .HO. 



h, 



Chemical Relations. 



Properties. This acid, which has also been named butyro-acetic 

 acid and propionic acid, forms, when in a concentrated state, a 



* Ann. de Chein. et de Phys. 3 Sen, T. 21, pp. 448-457. 



