Il8 HODGE. [Vol. VII. 



Expressed in per cent, 75 + % of the nuclei in the resting gan- 

 glion contained nucleoli to 15+ % in the stimulated. The sev- 

 enth and eighth pairs, stained in other ways (Kleinenberg's 

 haematoxylin and by Weigert's method), gave no such result. 

 In fact, the phenomenon could not be made to reappear in any 

 subsequent experiment. 



Next, three similar frogs were taken, each with a control ; 

 each was given the same amount of curare and the right sciatic 

 nerves of the three were stimulated continuously one, two, and 

 three hours respectively. From the nine stimulated ganglia no 

 effect of activity could be made out. 



Frogs 5 and 6 were used respectively to test the effect of 

 curare and the extent of post-mortem changes in ganglion cells, 

 with results that do not concern us here farther than to say that 

 the use of curare was abandoned ^ and the ganglia were excised 

 as quickly as possible after death. At this point it was also 

 decided to use intermittent instead of continuous stimulation. 



Frog No. 7 was made reflex, and the right brachial and sciatic 

 plexuses were stimulated, with two minutes' stimulation alter- 

 nating with two minutes' rest, for two and a half hours. Marked 

 differences between the cells of the two sides are clearly visible. 

 Perhaps the most pronounced of these, a difference noted inde- 

 pendently by a number of observers, is that the nuclei appear 

 shrunken in the stimulated ganglia. This led to the series of 

 measurements summarized in the following table. The nuclei 

 were measured, long and short diameters in sets of one hundred, 

 fifty stimulated and fifty unstimulated being taken from as 

 nearly corresponding sections of the two ganglia as possible. A 

 definite rule precluded wilful selection of the cells to be meas- 

 ured, this rule being that only nuclei containing nucleoli should 

 be measured, and that all such should be taken in the order of 

 their occurrence in the section. Measurements were made with 

 an eye-piece micrometer to the nearest /u. under magnification of 

 Leitz oc. 3, obj. 7 {= 600 diameters). 



^ Landois and Sterling, Physiology, p. 523, reads: "But when the action of the 

 drug (curare) is fully developed, no amount of stimulation of the skin or the posterior 

 roots of the nerves will give rise to a reflex act, although the motor nerve of the liga- 

 tured limb is known to be excitable." My experiment on frog 5, in which all but the 

 sciatic nerve, bone and all, was severed^ gave exactly the above result. The reason 

 for absence of results, however, in my case, may have been continuous stimulation or 

 curare or both. 



