64 ELBERT CLARK 



Still others show complete collapse.'* The greatest variety of 

 symptoms are manifested by various birds, but loss of control 

 of the legs is the most frequent. Fowls showing the latter symp- 

 tom, with otherwise fair to good general condition, were the ones 

 selected for this study; nerves of these show a more pronounced 

 degeneration, and recovery in this class of fowls is more easily 

 accomplished. Twenty to thirty days on the white rice diet is 

 the usual length of time before symptoms of neuritis are mani- 

 fested. Some birds resist for 35 or 40 days, and two fowls^ that 

 were receiving a small quantit}^ of calcium lactate with the 

 rice did not 'come down' till the fifty-first and sixtieth day 

 respectively. Nitrogenous and fatty foodstuffs in very small 

 amounts added to the rice also greatly defer the development 

 of the neuritis. For more complete data on this interesting affec- 

 tion and for feeding experiments, reference should be made to 

 the recent article by Vedder and Clark ('12). 



DEGENERATION 



A few remarks should be made at this point concerning the 

 nature and extent of the degeneration in the meduUated fibers 

 of the sciatic nerve in fowls of the class under consideration. 

 In the nerves of 60 chickens, which had been fed 20 days or 

 more on an exclusive diet of polished rice, degeneration in the 

 fibers of the sciatic nerve was observed by the aid of the Marchi 

 method in every case regardless of what symptoms were mani- 

 fested by the fowl before death. Many of these were confirmed 

 by the Weigert method for staining the myelin sheath. Several 

 fowls fed as long as 35 to 40 days showed no signs of weakness 

 in the legs but well marked nerve degeneration. The nerves 

 from each of twelve fowls fed from 7 to 22 days consecutively 



* Several workers have observed that fowls occasionally do not lose weight 

 on the polished rice diet. Frazer and Stanton ('11) who have kept very complete 

 records report several fowls which kept their weight up for as long as 35 days. 

 Other fowls even showed a gain in weight. 



^ Courtesy of Dr. R. B. Gibson of the Department of Physiology; from experi- 

 ments being conducted by him to study the influence of an addition of various 

 salt mixtures to the white rice on the production of this affection, to be reported 

 shortly. 



