232 EEYIEWS. 



conductors in tlie spinal cord are not so arranged, as to follow 

 distinct channels, running in bundles, in continuation of the nerve 

 roots, nor does it seem probable that such is true for the conductors 

 of pain, touch, tickling, &c. Indeed this, among other things, would 

 incline one much more to regard the spinal cord as a nerve tubule on 

 a very large scale, than as a large nerve composed of many indepen- 

 dent conductors, as has been the view of many : looked upon as a 

 gigantic nerve tubule, the spinal cord may be considered as having, in 

 its investing membrane, a structure analogous to the tubular membrane 

 of a nerve fibre ; and in the white structure of the columns, anterior, 

 lateral and posterior, the structure represented by the white substance 

 of Schwann ; while the grey medullary substance takes the place of the 

 axis cylinder. Of course this comparison merely serves to point out 

 an ideal similitude ; nevertheless, as • it seems probable that the axis 

 cylinder, encased and insulated as it is by the surrounding tunics, can 

 be the means of conveying sensations produced by divers means of 

 irritation, so it seems that there is some reason to suppose that the 

 grey matter conveys all sorts of impressions, and even also the orders 

 of the will to muscles. 



If we divide transversely, in the dorsal region, the whole posterior 

 half of the grey matter and a part of the lateral columns, besides the 

 posterior columns, we find that the voluntary movements are much 

 diminished in the abdominal limbs. If the division be carried further, 

 so that the whole of the central grey matter be divided, the animal can 

 hardly move its abdominal limbs, and if we add to this section that of 

 the anterior horns of grey matter, the loss of movement seems to 

 become complete, although the anterior columns continue undivided. 

 Hence it seems that, not only is the grey matter the conductor of 

 sensitive impressions, but that also the commands of the will to muscles 

 in a great degree pass along it : nay, more, that in making a gradual 

 division of the grey matter, power of voluntary movement is by degrees 

 diminished more and more, until it is entirely lost in the abdominal 

 limbs, while yet the anterior columns remain undivided. 



In the fifth, sixth, seventh and eighth Lectures, Dr. Brown-Sequard 

 enters upon an analysis of pathological cases, bearing upon the views 

 which he has elucidated, by experimental research in the preceding dis- 

 courses. We have already said that it is not our intention to enter 

 here upon the consideration of the pathological portion of Dr. Brown- 

 JSequard's work : we shall therefore content ourselves with saying upon 

 this subject, that although, after a careful perusal of these chapters, 

 we cannot in all respects coincide with the deductions drawn by the 

 accomplished author from the cases he details, yet that it is obvious 

 throughout, that he never seeks to coerce phenomena and symptoms 

 into harmony with any definite scheme of his own creation ; that his 

 only object seems to be the discovery of truth, not the framing of a 

 systematic but baseless fabric. We pass then directly to the latter 

 chapters, in which the functions and relations of the yaso-motor por- 

 tion of the nervous system are considered, or/ in other words, leaving 



