412 TOKUYASU KUDO 



Brain 



The brain in some cases appeared markedly congested at 

 autopsy. In the acute-thirst series the brain apparently remains 

 nearly constant in average weight with an insignificant increase 

 of 0.12 per cent (table 2). In the chronic-thirst series the average 

 brain weight lost 4.2 per cent. The ininvidual variations are 

 small (table 1). In the rat (Si. 2) on total inanition the corre- 

 sponding apparent loss in the weight of the brain is 7.6 per cent. 

 The mean brain weight for the controls was about 7 per cent 

 below the table value for rats of this length (Donaldson, '15). 



The data available in the literatm'e concerning the effects of 

 thirst on brain weight are somewhat contradictory. Falck and 

 Scheffer ('54) in a dog losing 20.7 per cent in body weight, noted 

 an apparent gain of 7.2 per cent in brain weight. Bowin ('80) in 

 rabbits on dry food with 50 per cent loss in body weight, noted 

 an absolute decrease (but relative increase; amounts not stated) 

 in the brain weight. Tobler ('10), in three dogs after experi- 

 mental diarrhea with loss of 22 to 30 per cent in body weight, 

 observed an apparent gain of 4.2 to 13.7 per cent in brain weight. 

 The increase in weight might perhaps be due partly to the con- 

 gestion or to indi^ddual differences between the test animals and 

 the controls. 



As to the effects of ordinary inanition, it has long been known 

 that of all of the organs, the central nervous system is one of the 

 most resistant to changes in weight. Jackson ('15) found an 

 apparent loss of only 5 or 6 per cent in the brain of rats subjected 

 to acute or chronic inanition (with water) and cites from the 

 literature numerous data indicating little or no change in brain 

 weight in other animals. On the whole, it appears evident 

 that, during thirst, both acute and chronic, as well as during 

 ordinary acute and chronic inanition with or without water, 

 there is but little change (usually a slight decrease) in the weight 

 of the brain. McCarrison ('19), as an effect of vitamine-deficient 

 diets, finds an apparent slight decrease in the brain weight of 

 pigeons, but an increase (average 1/7) in monkeys. 



