PHYSIOLOGICAL EXPERIMENTATION. 179 



under the title " Idea of a New Anatomy of the Brain." In support of 

 this statement Mr. Shaw cited certain passages from Bell's very scarce 

 tract, which, read in the light of subsequent events, seemed an ade- 

 quate justification of it. But, unluckily for the credit of both, a copy 

 of the tract had found its way into the possession of a certain Mr. 

 Alexander Walker, who had claims of his own to advance ; and he re- 

 printed it in full in a thin volume (now before me) published anony- 

 mously in 1839, under the title of " Documents and Dates of Modern 

 Discoveries in the Nervous System." 



I well remember the sensation which was produced at the time, 

 among those who took an interest in the subject, by this publication ; 

 from which it plainly appeared that the fundamental conception enun- 

 ciated in this " Idea " had gone no further than this " that the nerves 

 of sense, the nerves of motion, and the vital nerves, are distinct 

 throughout their whole course, though they seem sometimes united in 

 one bundle ; and that they depend for their attributes on the organs 

 of the brain to which they are severally attached " ; while, in carry- 

 ing out this conception, Bell, misled by his anatomy, had gone alto- 

 gether wrong. 



This doctrine was by no means new. It had been known from a 

 very early period that our limbs can only feel or move (I use these 

 words in their ordinary sense) by virtue of the nerve-trunks which 

 connect their skin and muscles with the spinal cord, and through it 

 with the brain. And although, when a limb is paralyzed, it is usually 

 deprived at the same time of feeling and of motion, yet as cases were 

 occasionally observed in which motion was lost without feeling, or 

 (more rarely) feeling was lost without motion, the idea arose that two 

 distinct sets of fibers may be bound up in the same trunks ; one for 

 feeling and the other for motion or, as we should now express it 

 more scientifically, one set conducting impressions made on the sensory 

 surfaces toward the central sensor ium, while the other transmits nerve- 

 force from the motor centers of the nervous system to the muscles 

 which it stimulates to contraction. This idea found distinct expres- 

 sion in the writings of certain ancient medical authors ; and cropped 

 up from time to time in modern medical literature, some writers ap- 

 proving it, while others dissented from it. And it was formally ad- 

 vanced in 1809 by Mr. Alexander Walker, who, in a paper entitled 

 " New Anatomy and Physiology of the Brain in Particular, and of the 

 Nervous System in General," published in the " Archives of Universal 

 Science " for July in that year, argued that " medullary action " (or, 

 as we should now say, a nerve-current) "commences in the organs of 

 sense ; passes, in a general manner, to the spinal marrow, by the an- 

 terior fasciculi of the spinal nerves, which are, therefore, nerves of 

 sensation, and ascends through the anterior columns of the spinal 

 marrow, to the hemispheres of the cerebrum," in which he located 

 the sensorium commune. Thence he traced his " medullary action " 



