EFFECTS ON THE PERIPHERAL NERVOUS SYSTEM 209 



fixed in Mliller's fluid and stained by Weigert-Pal method). There is also 

 hyperemia and proliferation of the connective stroma, and the markedly 

 atrophic nerve fibers may be separated by a granular substance apparently 

 derived from the degenerated fibers. 



The effect of various methods of dehydration upon the nerve cells in the 

 spinal ganglia and cord of rabbits was studied by Brasch ('98) who found finely 

 granular degeneration of the Nissl substance in extreme cases only. The 

 nuclear changes are more prominent and present two types: (a) nucleus rather 

 small and pycnotic (sometimes karyorrhexis) ; (b) nucleus large, with stellate 

 masses of variable stainability around the nucleolus. The former type appar- 

 ently develops more slowly, the latter more rapidly; and transitional forms 

 occur. The changes are apparently physical rather than necrobiotic, and are 

 capable of recovery upon restoration of water. 



Fig. 67. — Two degenerated nerve fibers (Pal stain; teased preparation) from the sciatic 

 nerve of a young fowl subjected to aqueous inanition (dry diet). The axone is visible in the 

 upper fiber. X600. (Pernice and Scagliosi '95a.) 



In young albino rats (1 month old) held at nearly constant body weight by a 

 relatively dry diet for various periods (see Table 10), Kudo ('21a) found a con- 

 tinued growth in the weight of the sciatic nerves, similar in most cases to that 

 in the spinal cord. With adult rats in the acute thirst series (body loss 36 per 

 cent), he found an apparent average loss of 21.3 per cent in the weight of the 

 sciatic nerves; and in the chronic thirst series (body loss 52 per cent) a loss of 

 22.1 per cent. This would indicate that in adults the loss during thirst (aque- 

 ous inanition) is relatively greater in the peripheral than in the central nervous 

 system, according to the data cited in Chapters X and XL This may be due 

 partly to the atrophy of adipose tissue which occurs normally intermingled in 

 the trunk of the sciatic nerve; but it nevertheless is in harmony with the findings 

 of Pernice and Scagliosi (above cited), who described an atrophy of the sciatic 

 nerve fibers. 



