108 VICTOR E. SHELFORD. 



because fat can be easily split to yield water. Pernice and 

 Scagliosi ('95) worked upon the histology of fowls which had 

 died of water starvation. They state that atrophy of the adipose 

 tissue, muscles and abdominal organs occurs. There is also 

 congestion and drying of the abdominal viscera. The authors 

 found that the structural elements of the tissues, including the 

 nervous system, had atrophied. They came to the conclusion 

 that the possible water fluctuation of the animal tissues is very 

 small and whenever a cell's water content passes a certain limit, 

 death ensues. 



All animals produce some water through the oxidation of the 

 hydrogen in their food. According to Atwater (Hill, '06) man 

 produces about one third to one fourth of the amount of water 

 which he gives off through the skin and lungs. Mathews ('13) 

 called attention to this fact in connection with the adaptation 

 of reptiles to desert conditions. Burger ('07) studied the water 

 relations of the meal worm (Tenebrio molitor) when kept in dry 

 air and fed on bran which had been dried at 105 C. He con- 

 sidered that the animals were in essentially absolute dryness. 

 Here they lived for weeks but lost weight. He found however 

 that the per cent, of water in the animals remained practically 

 the same until after death and came to the conclusion that the 

 insect larvae could not use their food to produce water and so the 

 living substance itself was used. No doubt the food taken pro- 

 duced water but this was not sufficient in quantity. The most 

 important fact brought out was that the per cent, of water re- 

 mained about the same in spite of the extreme dryness and rapid 

 loss of moisture. 



No mechanism to prevent loss of water exists in the common 

 frog; its water demand is supplied through the skin. Durig ('01) 

 found that the common European frog died if the loss of water 

 was rapid when 15 per cent, of the frog's weight was withdrawn. 

 If the drying was slow the frogs could lose 30 to 39 per cent, of 

 their weight in water without dying. When the weight was re- 

 duced to 61 per cent, the blood corpuscle count was increased to 

 23/2 times the normal. 



We note from the changes in activity due to withdrawal of 

 water, inactivity brought out in the preceding pages, that there 



