GENERAL PROPERTIES OF THE SPINAL CORD. 275 



deep portions of these columns. The experiments of Lon- 

 get, for example, made in 1840, have been repeatedly con- 

 tinued by more recent observations. Longet exposed the 

 lumbar portion of the cord in a large-sized dog and divided 

 it transversely. Galvanization of the antero-lateral columns 

 of the inferior portion always produced convulsive move- 

 ments, while the result of irritation of the posterior columns 

 was simply negative. On the other hand, galvanization of 

 the posterior columns of the superior segment of the cord 

 produced intense pain, and no effect followed irritation of 

 the antero-lateral columns. 1 These results, being positive, 

 are to be accepted in opposition to the negative results 

 obtained by Chauveau, provided it can be shown that the 

 stimulus did not extend from the cord to the roots of the 

 nerves, a reservation which is important in all experiments 

 in which the nerves are irritated with galvanism. Upon 

 this point, we have some experiments, made in 1863, which 

 will be detailed after we have discussed the properties of the 

 posterior columns. 



With regard to the posterior columns, the views of Chau- 

 veau are in advance of those of previous observers, only in 

 so far as he has shown that, although the surface of this 

 portion of the cord is endowed with sensibility, its deeper 

 portions are entirely insensible, except in the immediate 

 proximity of the posterior roots of the nerves. 



In view of the importance of the question under consid- 

 eration, and of the contradictory results of experiments, we 

 repeated, in 1863, the experiments of Chauveau, under con- 

 ditions as nearly physiological as possible. We had often 

 had occasion to note the diminished sensibility of the roots 

 of the spinal nerves immediately following the very severe 

 operation of opening the spinal canal, and had also noted 

 that the sensibility increased, probably approaching the nor- 

 mal standard, after the animal had been allowed a few hours 



1 LONGET, Anatomic ft physiologie du systeme nerveux, Paris, 1842, tome i., 

 p. 272, et seq. 



