270 REVIEWS. 



power of conducting impressions, and that its true function is 

 dynamical — that it is destined to produce nerve force. A moment's 

 reflection serves to show that every nerve, after separation from the 

 cerebro- spinal axis, nevertheless contains in itself the elements neces- 

 sary to originate the vis nervosa, or neurility, as it has been very well 

 named, for this force may be called into being by the excitation of 

 ever so small a portion of such a nerve by electrical, chemical or 

 mechanical stimulation. On the other hand, however much the 

 minute anatomist may have failed to point out precisely what becomes 

 of the roots of the nerves ; whatever discrepancies may exist among 

 the researches of Hannover, Stilling, Eigenbrodt, Blattmann, Kolliker, 

 Wagner, Lockhart Clarke, Schilling, Gratiolet, Owsjannikow, 

 Schroeder van der Kolk, Bidder, Remak, Kupfer, and others ; the 

 great majority of these anatomists, at least, agree that a great number 

 of the fibres from the posterior nerve roots pass directly into the 

 grey substance. In this fact alone, we have good anatomical evidence 

 that the grey matter is connected with the transmission of sensitive 

 impressions. "We find likewise strong presumptive evidence to the 

 same effect, in the circumstance that so many most skilful experi- 

 mentalists, engaged in investigations quite independently of each 

 other, and differing in some respects widely from one another, have 

 nevertheless agreed in attributing to the grey matter some share in 

 the transmission of sensitive impressions : the hypothesis of Marshall 

 Hall has nothing in it directly at variance with such a supposition ; 

 that of Todd and Bowman assumes that all nerves are implanted in 

 the grey matter, and do not pass beyond it, and that the segments of 

 the cerebro-spinal axis are connected with each other through the 

 continuity of the grey matter ; while Bellingeri, Valentin, Schiff, Van 

 Deen, Yolkmann, Stilling, and other physiologists, are led by their 

 experiments, however contradictory in other respects, to grant to 

 the grey matter conducting power. 



The greater part of Dr. Brown- Sequard's lectures are devoted to 

 an attempt to determine with scientific precision, what are the exact 

 channels in the spinal cord and medulla oblongata through which 

 sensitive impressions are transmitted and through which the influ- 

 ence of the will is conveyed to muscles ; in making this attempt, Dr. 

 Brown- Sequard has recourse to experimental investigation on ani- 

 mals, while he also tries to corroborate the conclusions thus arrived 

 at by reference to pathological cases ; and even those who may not 

 regard his arguments as in all respects conclusive, we venture to assert, 

 will not peruse his book without admitting that he gives a masterly 

 analysis of the pathological cases bearing upon these questions, 

 which he has collected from the most varied sources, with so much 

 labour and so much care. As an experimentalist, he has disproved 

 the assertion of one of the most eminent physiologists that these 

 islands has ever produced, that " direct experiments afford no aid 

 in determining the functions of the columns of the spinal cord." "We 



