As regards these analyses, which are quoted from Simon's work on animal che mistry, it would appear a matter of regret that experiments have not been made on an extended scale on the same animal, under different conditions ; more especially under variations in food, temperature, and moisture. Such form of inquiry could not fail to be of eminent service to physiology, and much light might thus be thrown on the question of diet, in respect to constitution and predis position to disease, a subject greatly needing elucidation, notwithstanding the labour and ingenious activity which has been devoted to it during the last few years.
Urine of Birds, &c. — The urine of birds is excreted from the cloaca in the form of a thin paste, which hardens by exposure. Urate of ammonia is the principal constituent. The urine of carnivorous birds, however, contains urea in considerable quantity, which distin guishes it from that of birds feeding on vege table substances. Chemists have also described a green colouring matter, as peculiar to the urine of carnivorous birds.
The constituents of the urine of the ostrich, according to Vanquelin and Fourcroy, are— Uric acid.
Sulphate of potassa.
Sulphate of lime.
Chloride of ammonia.
Oily matter.
' A peculiar animal matter.
Acetic acid (?) The urine of serpents is excreted in the form of a white, earthy mass. It is made up
of uric acid, combined with potassa, soda, and ammonia. Phosphate of lime is also present.
Cass and Henry state that they obtained urea from the urine of serpents. That prin ciple was sought for in vain, however, by Vanquelin and Fourcroy.
Simon gives the following as the result of an analysis of the urine of a rattle-snake. He operated on 100 parts, weighed, when quite dry.
Free uric acid, some fat, and ex- 1 56-4 tractive matters - J Urate of ammonia - - - 31.1 Urate of soda, with some chloride 1 of sodium - - Urate of lime - - - 1.4 Phosphate of lime - - - 1.3 Dr. J. Davey examined the urine of the bull-frog (rana taurina). He found it of spe cific gravity 1003. Urea, chloride of sodium, and a little phosphate of lime were also pre sent.
Marchand's analysis of the urine of the land-tortoise (testudo tubulata) yielded the following result, Water - - - - - 950'64 Urea - - - - - 6.40 Uric acid - - - - 17.25 Salts and indeterminate organic 2510 matter - - There was no hippuric acid in this urine. It possessed a faintly acid reaction, and is stated to have presented the appearance of pus. Ether extracted a brownish-coloured fat, having an urinous odour.*