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vitality in the spinal cord itself. But this experiment is not 

 decisive, because sometimes it occurs that such a mechanical 

 excitation in frogs, which have not been poisoned, produces 

 tetanus. Nevertheless I must say that the tetanus in this last 

 case is never so violent as in poisoned frogs. 



A better experiment is to excite slightly with a needle, the 

 posterior columns of the spinal cord. Then, tetanus constantly 

 occurs in poisoned frogs, although the sensitive roots are divided, 

 and it very rarely occurs in frogs that are not poisoned. 



I have already published* the following experiments, which 

 are much more decisive against the hypothesis of Stannius : 



A ligature is put around the aorta of a frog, near its termi- 

 nation in the abdomen, and consequently the posterior limbs 

 cease to receive blood. Then the frog is poisoned with strych- 

 nine introduced into its mouth, and after a few minutes the 

 convulsive phenomena take place. 



In this experiment the nerves of the posterior limbs do not 

 receive strychnine, whilst the spinal cord receives it ; therefore 

 convulsions are not produced ia consequence of an action of 

 strychnine on the sensitive nerves of the skin, as Stannius has 

 supposed, but in consequence of its action on the spinal cord. 



Now, if we poison a frog after having divided the spinal cord 

 at the brachial enlargement, and after the section of all the 

 small arteries giving blood to the spinal column, we see that 

 convulsions do not take place in the posterior limbs, although 

 the reflex faculty is not lost in consequence of the cessation of 

 the circulation in the spinal cord, and that it remains for half an 

 hour or a little more in summer, and about two hours in winter. 



In this experiment, blood containing strychnine reaches the 

 sensitive nerves of the posterior limbs, and not the spinal 

 cord, and there are no convulsions; therefore it is not on the 

 sensitive nerves that strychnine acts in order to produce con- 

 vulsions. 



These two experiments are evidently decisive. In the first, we 

 see that when blood containing strychnine reaches the spinal 

 cord, and not the cutaneous nerves, there are convulsions ; 

 and in the second, we see that when blood containing strychnine 

 reaches the sensitive nerves and not- the spinal cord, there 

 * Gaz. Med. de Paris, 1849, p. 745. 

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