DIMINUTION OF SENSIBILITY. 
307 
sensibility in certain portions of the frame are recorded in the 
annals of human medicine : we have not had much opportunity to 
observe this, or have not availed ourselves of it, in veterinary 
practice. A gentleman, however, under the title of a “ certified 
practitioner,” ( 1 know him well ; why should he scruple to sanction 
with his real name important contributions to our art?) has de- 
scribed one that possesses some interest. The sphincter ani, and 
that of the bladder of a mare, were paralyzed, as were the muscles 
of the tail and croup; the tail dangled up and down in a singular 
way as she trotted. The parts were perfectly insensible, for she 
shrunk not when she was pricked with a pin. The upper lip 
was afterwards attacked and drawn on one side. She partially 
recovered by the administration of laxatives and tonics and 
blisters, so that she could feed and retain or discharge her dung 
as she pleased*. 
Insensibility of the mucous Membrane of the Bladder . — 
There are few practitioners who have not observed a certain 
degree of incontinence of urine in horses that have anchylosis or 
stiffness of the spine. May not this be referrible, in some 
cases at least, to insensibility of the lining membrane of the 
bladder, more than to want of power in the sphincter muscle ? 
It is the stimulus of the urine on the mucous membrane which 
governs the motions of the sphincter; and when the bladder 
becomes insensible to the presence of the urine, the sphincter 
will cease to actf . 
Flying Lameness. — How many cases of flying or periodical 
lameness may be accounted for by pressure on the course of 
certain nerves ! If any nerve is long and unduly pressed upon, 
a numbness steals over the limb with which it is connected, 
and the unconsciousness of the true bearing and action of this 
will produce as awkward and as veritable lameness as any want 
of power in the muscles of the limb. 
The Tourniquet.—' The application of a ligature to a limb 
diminishes or suspends its sensibility in the part further removed 
from the source of the nerve, and that either by the mechanical 
pressure on the nerve or the interruption of the circulation; and 
therefore it is that the application of the tourniquet is not only 
useful in temporarily controlling the bleeding, but in lessening 
the suffering of the patient during a serious operation. 
The division of the trunk or of the ramification of a sensitive 
nerve produces temporary or permanent loss of feeling in the 
parts beyond, which were supplied by that nerve. This, however, 
is a most important branch of our subject, and will be considered 
in the next lecture. 
* Veterinarian, ix, 136. fTonD, Cyc. Pract. Med. iii, 242. 
