WATER ITS RELATION TO METABOLISM 261 



of the plasma rising from 8-8 to IT 6 per cent., the red corpuscles 

 from 4-8-5-58 million per c.mm., and the specific gravity of the 

 serum from 1027- 4-1033-4. Equilibrium was soon established by 

 the tissue juices passing into the blood, and a repetition of the 

 experiment produced little effect. Attempts have been made to 

 drain the fluid from dropsical tissues into the blood by restricting 

 the water intake, but the results have not been commensurate 

 with the discomfort caused. The problem of dropsy is a 

 complex one, for the permeability of the capillary wall and the 

 osmotic pressure of the tissue cells are altered either by a 

 deficient circulation, bacterial infection, or other abnormal con- 

 dition of the blood. 



In cases of severe and extensive burns and cholera the blood 

 thickens, the urine rises in sp. gr. to 1037-1040, and spasms may 

 occur, possibly from the drying of the neuro-muscular system. The 

 blood in cholera may lose 6-4 per cent, of its water, and if the loss 

 from the tissues were in the same ratio, the total loss from a man 

 weighing 70 kg. would be 4-5 kg., or about 10 per cent, of the body 

 water. 



To sum up, then while a fasting mammal can use up almost 

 the whole of the body fat and 50 per cent, of its proteid before 

 dying, a thirsting one becomes moribund when it has lost little 

 more than 10 per cent, of its body water. 



Some of the lower animals, such as frogs, can be dried to a 

 far greater extent without loss of life. When kept in a dry glass 

 chamber fasting frogs may lose 25 to 30 per cent, of their weight 

 in 2-3 days, while the same frogs if kept in water only lose J-f 

 per cent. By gradual drying Durig has diminished the weight of 

 a frog by no less than 39 per cent, without killing it. On the 

 other hand, the rapid loss of 15 per cent, of its water killed a 

 frog. In the case of a frog, dried 30 per cent., the blood -corpuscle 

 counts increased from 1 to 2J- millions. The brain and heart lost 

 relatively less water than the other organs. 



Frogs take up water through their skin : they do not drink. 

 A thirsting frog with gullet tied increases in weight in a moist 

 chamber no less than one with the gullet open. The absorption 

 through the skin can be easily demonstrated by placing the frog in a 

 bath of dilute ferric chloride after injecting a solution of potassium 

 ferro-cyanide into the dorsal lymph sac. A blue band is soon 

 seen on section of the skin. Reid found that fluid is more easily 



