EFFECT OF ACTIVITY ON NERVE CELLS 353 



of camera lucida outlines of cells and nuclei. This was done in 



four experiments Five cells of each type and after 



each fixative seemed to give a fair average." Dolley's miterial 

 in which consecutive stages were studied did not receive the same 

 treatment as to fixation, staining, mounting, and cutting. The 

 control and fatigue material was handled entirely separately 

 (Amer. Jour, of Physiol., vol. 25, p. 155). Slight unavoidable 

 variations in the exposure of the tissue to the various agents 

 and different thickness of the cut sections would make such 

 material worthless for comparative study. As pointed out above, 

 this objection cannot bo applied to my o^^^l experiments, as the 

 handling of material was identical in all cases. Dolley's method 

 of measuring size of cells and luiclei is o])eii to serious objection. 

 In the Journal of Medical Research, volume 21, he .states, "While 

 not adapted for exact measurement on account of their shape, 

 the largest diameters (cells and nuclei) were always taken." 

 In my own experiments the actual relative areas of the nuclei 

 and cells was computed with the use of the polar planimeter, 

 which traces the entire outline of the cell and gives very accurate 

 results. As seen in the table, I found no difference in the size of 

 the cells of the control and exercise aninuds. 



Electrical stimulation {gdlvanic) 



Experiment 6. Pigeons. In this experiment a i)if;eon was fastened 

 by the feet in a standing position, while a wire from four 50 amperes 

 galvanic i)atteries was wrapped around the legs. A current was al- 

 lowed to i)ass through the wire once a second hy a clock make and hreak 

 arrangement. With the entrance of the stimulus there was a strong 

 contraction of the leji; and iIukIi nuisclcs. After four hours the con- 

 tractions became feei)le. owing to fatigue, and the pifjeon was killed. 

 Rigor mortis of the leg and thijih muscles set in innnediately. A con- 

 trol pigeon was killed at the same time. 



^Microscopic study revealed absolutely no constant morphological 

 differences in the anterior horn cells and in the dorsal gansHon cells 

 from the two birds. 



Faradic stimulation 



Experiment 7. Faradic stimulation of the sciatic nerve in a cat was 

 appHed in this experiment. A cat weighing 2 kilos was anaesthetized 

 with ether, and decapitated according to the method of Sherrington by 



