xiv COMPARATIVE PHYSIOLOGY. 



PAGE 



Experimental 413 



Absorption by the skin 413 



Comparative 413 



Summary . ......... 413 



Excretion by the Kidney 415 



Anatomical . 41.5 



Comparative . . 415 



Urine considered physically and chemically 419 



Specific gravity . . . . . . . . . .419 



Color 419 



Reaction . . 419 



Quantity ... 419 



Composition : Nitrogenous crystalline bodies . . . 420 



Non-nitrogenous organic bodies 420 



Inorganic salts 420 



Abnormal urine .... . . . 421 



Comparative .421 



The secretion of urine ........ 421 



Theories of secretion 421 



Nervous influence 423 



Pathological . 423 



The expulsion of urine . . 424 



General .424 



Facts of experiment and of experience ..... 424 



Pathological 426 



Summary of urine and the functions of the kidneys .... 426 



Comparative ..... .... 426 



The Metabolism of the Body . 428 



General remarks .... .... 428 



Tlie metabolism of the liver 428 



The glycogenic function . . . . . . 429 



The uses of glycogen ... .... 429 



Metabolism of the spleen .... .... 429 



Histological ... 430 



Chemical . . 430 



The construction of fat ........ 432 



General and experimental 432 



Histological 433 



Changes in the cells of the mammary gland . . 484 



Nature of fat formation ... . . 434 



Milk and colostrum . . . . . . . . .435 



Pathological . . ... ... 435 



Comparative . . ....... 436 



The study of the metabolic processes by other methods . . . 436 



