238 
ANIMAL PATHOLOGY. 
ceptible of certain impressions, pleasurable or painful, referrible 
to the general well-being of the animal, the others being inti- 
mately and necessarily connected with the mind. We cannot, 
however, maintain this distinction in a pathological point of 
view. 
Divisions of these Lesions. — These sensitive nerves are the 
media through which impressions relating to the organic, or the 
animal, or the intellectual life, are conveyed to the common sen- 
sorium ; and we can only conceive of three modes, and applica- 
ble to them all, in which they depart from their healthy function, 
namely, when they are too acutely or not sufficiently sensible to 
impression, whether from external or internal causes, or when 
they convey impressions not simply too vivid or too obtuse, but 
otherwise wearing a delusive character. I need not remind you 
that, in this investigation, we have nothing to do with the nerves 
of pure sensation deriving their origin from the base of the brain : 
they will afford matter for future consideration. 
The Sensitive Nerves distributed to every Part.— The nerves 
proceeding from the central columns of the superior surface of 
the spinal cord are not only, according to their relative position, 
determined in an especial manner to certain parts connected with 
animal life, and to which they essentially belong, — perhaps I 
must not say that they anastomose with other nerves, for it is 
evidently necessary that the impression, pleasurable or painful, 
beneficial or injurious, should be referrible to the precise point 
on which it is made, and that no painful feeling should spread 
around, unless when some injury is extending, and needs instant 
remedy — I must not say that they anastomose with other nerves, 
but they ramify into innumerable branches of extreme minute- 
ness, and spread themselves over every portion of both sys- 
tems. They do so in order to be everywhere the organs of 
pleasure or of salutary warning; and they keep up a common 
feeling and a common sympathy, on which the well-being of the 
system and the proper action of every part depend. 
Their natural State. — Are they in a quiescent state when the 
animal is unconscious of any determinate pleasure or pain ? — 
No, they can never be altogether quiescent ; there is a feeling 
of health, not easily to be described, but having a real and de- 
lightful existence when the various parts of the frame are work- 
ing harmoniously and well ; and there is a real and tvearisome 
sensation when disease is about to attack the frame. There are 
certain acts in which the excitement of a portion of the nervous 
system is attended by a great degree of pleasure; but, generally 
speaking, an undue excitement is accompanied by or degenerates 
