NUTRITION 



289 



an increased produc- 

 tion of heat. But it is 

 not necessary to pos- 

 tulate special nerves 

 presiding over this pro- 

 cess, since the heat 

 produced in muscular 

 contraction is in itself 

 sufficient to account for 

 the fact. The reader 

 may be reminded of the 

 shivering in fever and 

 in the waking up of 

 animals from hiberna- 

 tion, in which latter 

 process the heat pro- 

 duced by muscular 

 activity serves to bring 

 up the temperature of 

 the animal to its nor- 

 mal height. Accord- 

 ing to Pembrey (1903) 

 a dormouse raises its 

 temperature by 19 in 

 forty-two minutes. 



Cathcartand Leathes 

 (1907) found the amount 

 of uric acid excreted to 

 be different according 

 to the manner in which . 

 the muscular contrac- 

 tion was produced. If 

 shivering was brought 

 on by exposure to cold, 

 a marked rise in uric 

 acid output resulted ; 

 whereas, if vigorous 

 voluntary contraction 

 was produced, there was 

 a marked fall in the 

 output. Although these 

 experiments do not 

 prove the existence of 

 nerves directly affecting 

 chemical changes, they * 

 suggest that different 

 kinds of innervation pro- 

 duce different chemical 

 reactions in the cells 

 affected. 



When cells are 

 known to be sup- 

 plied with nerve 

 fibres, it would be 

 rash to deny the 

 possibility of the cell 

 processes being influ- 

 enced by impulses 

 passing from the 

 fibres to the cells. 

 All that we are 

 justified in saying is 

 that there is, as yet, 



FIG. 77. PHOTOGRAPHS OF HISTOLOGICAL CHANGES IN THE 

 POSTERIOR ROOT GANGLION IN A CASE OF HERPES ZOSTER OF 

 THE LEFT SIDE OF, THE NECK. 



A , Normal third cervical ganglion of the right side. 



B, One of the inflammatory foci in the third cervical ganglion of the left side. 

 Both ganglia were cut in the same block, fixed on the same slide, and stained 



together by Nissl's method. 



Note the multitude of small dark cells in B, and the effects on the ganglion 

 cells. 



(Head and Campbell, 1900, PL 4.) 



