ITS INCIDENTAL CONSTITUENTS. 419 



stance, milk-sugar, starch, and fat. Magenclie* injected a solu- 

 tion of starch into the jugular vein of a rabbit that fasted for three 

 days, and whose urine was acid, clear, and rich in urea: the 

 urine almost instantaneously underwent a complete change, be- 

 coming alkaline, turbid, and poor in urea. Bernardf injected a 

 solution of grape-sugar into the veins of a dog and of a rabbit; 

 the urine of both animals was thus rendered alkaline and turbid 

 from the separation of earthy salts, while, under similar conditions, 

 a solution of cane-sugar exerted no such action on the urine, but 

 was carried off unchanged by that secretion. From these facts, 

 we may undoubtedly conclude that the alkalinity of the urine of 

 graminivorous animals does not solely depend upon the vegetable 

 alkaline salts contained in the food. Bernard, moreover, found 

 that the urine of dogs, which in the normal state is acid, be- 

 comes alkaline as soon as these animals are kept strictly upon 

 vegetable food ; and conversely, that the urine of rabbits, which 

 under normal conditions is alkaline, becomes acid as soon as ani- 

 mal food has been introduced into the stomachs of these creatures, 

 or a decoction of flesh is injected into their veins. From the 

 experiments which Bernard instituted on herbivora, whose urine 

 after the abstraction of all food was clear, of an amber-yellow 

 colour, and strongly acid, it follows that the pure metamorphosis 

 of tissue in the animal body, like a purely flesh diet, induces the 

 secretion of a limpid, acid urine. Finally, Bernard believes that he 

 has discovered that the pneumogastric nerves exert an influence on 

 the reaction of the urine; thus, for instance, he saw that the alkaline 

 urine of animals fed upon vegetables became acid after the section 

 of both these nerves a result whose accuracy I feel justified in 

 doubting, having myself performed a similar experiment on a 

 rabbit : rabbits are, however, by no means well adapted for such 

 experiments ; as far as my experience goes, these animals often 

 secreting an acid urine without any apparent reason for so doing. 



Quinine may be easily rediscovered in the urine after the use of 

 moderate doses. 



Urea, according to the experiments of Wb'hler and Frerichs, 

 passes unchanged into the urine. 



Theine and theobromine cannot be rediscovered in the urine: 

 since both these substances occasion intense excitement of the 

 vascular and nervous systems, I am unable to decide whether the 

 augmentation of the urea discharged in twenty-four hours, which I 



* Compt. rend. T. 23, P. 191. 

 t Ibid., pp. 536537. 



2 E 2 



