122 THE SECRETIONS: 



" These observations would seem to render the formation of 

 lactic acid in the body of the herbivorous and graminivorous 

 animals, which take starch and sugar in their food (substances 

 from which lactic acid may be formed), not merely possible, 

 but in many cases highly probable ; and yet, strange to say, 

 chemists have hitherto attempted in vain to detect lactic acid in 

 the urine of the cow and of the horse. The urine of the cow 

 or horse has no acid reaction ; on the contrary, its reaction is 

 strongly alkaline ; it contains carbonated, hippurated, or ben- 

 zoated alkali, or alkalies combined with mineral acids, but no 

 trace of any lactate. 



" In contrast with this, the urine of man, and of carnivorous 

 animals, manifests, when in a healthy state, a strongly acid re- 

 action. Now, it is precisely in analyses of the blood and urine 

 of man, and of carnivorous animals, that we find lactates men- 

 tioned as constant constituents ; not because they have in reality 

 been detected in these fluids for no one has as yet succeeded 

 in producing lactic acid therefrom but because, upon examin- 

 ing the aqueous and alcoholic extracts of blood and urine, some 

 non-crystalline matters have been found which sometimes mani- 

 fested an acid reaction, and upon incineration left a carbonated 

 alkali as a residue, thus presenting a remote similarity in deport- 

 ment to the alkaline lactates. 



" From what substance could lactic acid be formed in the 

 body of carnivorous animals ? With the exception of fat, they 

 partake of no non-nitrogenous matter in food, no substance, in 

 fact, so far as we know, capable of producing lactic acid. Car- 

 nivorous animals partake of no sugar, no starch, no gum, no 

 mucus ; there is a total absence of the non-nitrogenous sub- 

 stances which form so large a part of the aliments of herbivorous 

 and graminivorous animals. 



" The assumption, a priori, that neither the blood nor any 

 other fluid in the body of carnivorous animals can possibly con- 

 tain any lactic acid, has been positively established by the ex- 

 periments of Enderlin, (Annalen der Chemie und Pharmacie, 

 vols. 49 and 50.) Finally, Pelouze has proved that the experi- 

 ments of Henry, who pretended he had detected lactate of urea 

 in urine, are erroneous, and by no means to be relied upon. 



" Consequently, as our knowledge of this subject stands at 

 present, the acid reaction of urine cannot proceed from lactic 



