a. Source of the reflex faculty in the spinal cord. 



Notwithstanding the experiments of Redi, Whytt, Procbaska, 

 Unzer, Sdnac, Fontana, Caldani, Sir G. Blane, Fray, Legallois 

 and many other experimenters; and notwithstanding the much 

 more important experiments of Marshall Hall, Muller, Grain- 

 ger, Volkmann, Kurschner, Pickford, de Martino, Buchner, 

 Mayer, Paton and Stilling, the existence of the reflex faculty, 

 after the spinal cord has been separated from the encephalon, is 

 not considered by all physiologists as a proof of the independence 

 of the spinal cord. J. W. Arnold and Flourens still maintain 

 that the medulla oblongata is a centre, giving life to the other 

 parts of the nervous system. The reflex faculty possessed by 

 the spinal cord after it has been separated from the encephalon, 

 is considered by J. W. Arnold as a remainder of something given 

 to the spinal marrow by the encephalon, before their separation. 



My experiments prove the incorrectness of that opinion.* I have 

 found that after having exhausted the reflex faculty by putting 

 it in action, energetically and frequently, in an animal on whom 

 the spinal cord is separated from the encephalon, it reappears, 

 and becomes soon as energetic as before, provided that the cir- 

 culation of blood takes place in the cord. Moreover I have 

 found, that if the reflex faculty is put in action frequently, it is 

 able to produce an immense quantity of action : thus, for 

 instance, it can stimulate sufficiently the muscles of a frog's leg 

 to make them raise, in an hour and in divided portions, about twelve 

 pounds, to the height of about two lines. In a pigeon the reflex 

 faculty is able to stimulate the muscles of a leg so far as to make 

 them raise fifty pounds, by fractions, in an hour, to the height 

 of more than one inch.f 



I shall add two other decisive proofs : 1. The reflex faculty 

 is very weak in frogs immediately after the spinal cord has been 

 separated from the medulla oblongata, and it increases after- 

 wards, as R. Whytt and Marshall Hall have discovered. I have 

 stated that it increases so much that the posterior limbs are able 



* See : Recherches et experiences sur la physiologie de la moelle epi- 

 mere. These inaugurate. Paris, 3 Janvier, 1846. Comptes rendus des 

 seances de 1' Academic des Sciences. Paris, 1847 T. xxiv. p. 849. 



tSee Gaz. Med. de Paris. T. 4. 1849. p. 233. 



