OF THE CALABAR BEAN. 739 



In 1 hour 25 minutes, the right leg was drawn up in 145 beats. 



1 



, 30 



>> 





left „ 



158 



1 



, 35 



>j 





right „ 



160 



1 



, 40 



>> 





left „ 



180 



1 



, 45 



>> 





right ., 



197 



1 



, 50 



!> 



no 



reflex movement of either after 250 



Both sciatic nerves were found to be active when directly stimulated, but the contractions 

 were confined to the limb whose nerve was galvanised. 



This, and the experiment which precedes it, are conclusive in showing that 

 the diminution, and then destruction, of the diastaltic function are not interfered 

 with when physostigma is only prevented from acting on peripheral portions of 

 the reflex apparatus. When, however, it is permitted to act on the nerve endor- 

 gans, but is prevented from reaching the centres, the effect is very different. 



Experiment XLII. — (Temperature of Laboratory, 53° F.) 



I opened the abdomen of a frog, and, with great care, tied, and, in some instances, cut 

 through, all the blood-vessels that entered the spinal canal from the lower edge of the scapula 

 to the coccygeal extremity of the sacrum, and then divided the spinal column at the higher of 

 these points. By this means, the blood was only prevented from reaching a limited portion of the 

 cord ; so that, though unable to convey physostigma to the reflex centre for the posterior extre- 

 mities, it could still do so to those extremities themselves, and to all other parts of the body. 

 Voluntary movements of the limbs and of the body, anterior to the divided portion of the cord, 

 occurred when the frog was set free ; and irritation of the posterior parts was promptly followed 

 by reflected movements confined to them. The heart, which the operation had partially exposed, 

 was contracting sixty-eight times per minute. 



A large dose of extract was administered by the mouth. In twenty minutes, only very faint 

 reflex movements could be excited when the anterior feet were irritated, while gentle stimula- 

 tion of the posterior caused energetic reflex movements ; and the heart was acting at the rate 

 of eighteen per minute. In little more than an hour, the diastaltic function was completely 

 abolished in the anterior half of the body, while the conductivity of the brachial nerves re- 

 mained ; and, still, a slight pinch or weak galvanism of the posterior webs was followed by 

 pretty active reflex movements. The heart had now stopped. The diastaltic activity of the 

 posterior half of the body continued for two hours after it had disappeared in the anterior. 



The mere prevention of the access of physostigma to a segment of the cord, 

 while it was allowed to act directly on all other parts of the body, had, therefore, 

 the effect of delaying the loss of reflex function in the parts connected with that 

 non-poisoned segment. We have, already, frequently seen that protection of the 

 endorgans and of portions of the nerve trunks from the poison does not delay or 

 at all influence the gradual impairment and final destruction of the reflex function 

 that ensue on its access to the cord. The conclusion is only logical, that Calabar 

 bean produces a destruction of the diastaltic power by an action on the spinal cord. 



It is not superfluous to observe that I do not in these experiments ignore the 

 effect on the cord of mere stoppage of the circulation. When the heart is quickly 



* In all these experiments, the parts which had been dipped in the acid solution were imme- 

 diately washed with distilled water. The destructive action of the acid was thereby reduced to a 

 minimum. 



VOL. XXIV. PART III. 9 P 



