380 SEA-SIDE STUDIES. 



Everybody contradicted everybody. Vivisection seemed a 

 snare. It was Longet who put an end to the controversy by 

 explaining how the discrepancies necessarily arose, and by 

 establishing a uniforni plan of employing galvanism as the 

 test* The doctrine of Bell, as modified by Longet, became 

 the " doctrine of the schools." It is briefly this : All the phe- 

 nomena of reflex action depend on the vesicular substance, 

 which is itself entirely removed from the phenomena of sen- 

 sation or motion. The power of transmitting impressions 

 resides entirely in the white, fibrous substance, and of this 

 the posterior columns are exclusively devoted to sensoiy im- 

 pressions, the anterior and lateral columns exclusively to 

 motor influences. An impression is earned to the brain 

 by the posterior columns only ; and from the brain by the 

 antero-lateral colmnns only : the one awakens a sensation, 

 the other a movement. 



After having devoutly believed this theory for many 

 years, we are called upon to acknowledge that it is wrong in 

 every particular. In the presence of many distinguished 

 physiologists M. Brown-S^quard has demonstrated that sen- 

 sibility, so far from being destroyed, is actually increased by 

 section of the so-called sensitive columns ; while, on the other 

 hand, when a section of the chord was made which divided 

 it eveiywhere except in these " sensitive columns," sensibility 

 was totally destroyed. He proved, moreover, that it is the grey 

 vesicular substance of the chord — itself perfectly insensible — 

 which transmits both sensory and motor impressions. He 



* Longet, Anat.et Phys. du Systhne Nerveux, 1842. Sec his Traiti de Phj- 

 siolojie, 1850, vol. ii., where the history of the discovery is given. 



