94 CM. JACKSON 



body weight. The relative (percentage) weight is of course 

 correspondingly higher in the thin animals. 



In young animals during the period of active growth, the re- 

 sults of inanition (especially chronic inanition) are in general 

 somewhat different from those in adults, since the tendency of 

 the organs to maintenance is in the young animal complicated 

 by the growth impulse (Jackson '15). Bechterew ('95) found a 

 slight apparent loss in the absolute weight of the brain and 

 spinal cord of the newborn cat and dog during acute inanition. 

 Hatai ('04) found in a series of young albino rats subjected to 

 chronic inanition for 21 days an estimated average loss of about 

 5 per cent in the absolute weight of the brain. Later (Hatai 

 '08) in another group of young rats in which growth had been 

 retarded by underfeeding, he found that in these stunted ani- 

 mals the brain and cord had a weight approximately normal 

 for the corresponding body weight. Donaldson ('11), in still 

 younger rats held at nearly constant body weight by under- 

 feeding from age of 30 days to 51 days, finds an apparent in- 

 crease of 3.6 per cent in the weight of the brain. My own obser- 

 vations (Jackson '15), however, indicate little or no change in 

 the weight of the brain under these conditions. 



On the whole it appears that in adults inanition, both acute and 

 chronic, produces a sUght loss in the absolute weight of the 

 brain. In young, rapidly growing animals, however, it is doubt- 

 ful whether any such loss occurs, especially n chronic inanition, 

 where there is even a possible increase in brain weight. 



SPINAL CORD 



The spinal cord in the acute inanition series (table 3) has 

 an average weight of 0.631 gram and forms an .average of 0.41 

 per cent of the body weight. Calculations from Donaldson's 

 ('09) data indicate that at the average initial gross body weight 

 (244 grams) the spinal cord should weight 0.625 gram, forming 

 0.26 per cent of the body weight. The data would therefore 

 seem to indicate not only no loss, but even a very slight gain 

 of the spinal cord in absolute weight during the period of acute 

 inanition. In an earlier paper, Donaldson ('08) in table 4 gives 



