26 THE LIVER. 



point where it quits, "as it were," the central organ, to 

 its extreme distribution ; and what is usually called the 

 root of the nerve, or, more correctly, its point of inser- 

 tion, is but a portion of the peripheral distribution. By 

 taking this view of the subject, the doctrine of Jti/j- 

 thesia and anaesthesia obtains a more exetnsive significa- 

 tion ; as, -the mere casual and superficial examination of 

 the cutaneous nerves cannot, as it has hitherto done, 

 suffice to a correct diagnosis, and a successful treatment of 

 the many obscure forms of neuralgic diseases. It there- 

 tore becomes the more imp.-rative to examine carefully 

 the various fibres traversing the osseous canals, or pass- 

 ing over the brain and spinal cord, as distinct characters 

 indicate, to the close M in dif- 



.1 divisions of the ]>eiij>li t. It is lik< 



:>ase the dtirtiim- ,f the neuroses of | 

 bility upon the ]iliysi.l..^i<-al laws governing the n- 

 of sensation. These I 



First, Tin- /"in of isolated That Q6J 



only invents exalted or <i 



affected by t i or depre ; and the 



adjoining fibre, tii 

 not implicated. 



Secondly, The law of * : 



M, Here tl. ! propagated from th< 



originally excited to other centrij ves. 



Thirdly, The lair< Kvery 



sation, as it become- :ihle to consciou 



referred to the periphery of the sensitive fibre, the entire 

 tract of which, from its rommeixvmciit to its terminal 

 point, is susceptible of the impression. Sensation varies 

 according to the peculiar sphere of the affected n 



