THE GREAT SPINAL ORGANIC NERVE IN THE ABDOMEN. 237 
presently a prey to the full action of the narcotic ; the other lay 
quietly, or only exhibited the disordered respiration consequent 
on the operation . ” He gave an equal dose of nux vomica to two 
dogs, on one of which he had practised the division of these 
nerves. The one presently died, the other for awhile experienced 
no bad effect from the drug, nor did he begin to suffer until the 
time that the poison, or the influence of the poison, might have 
reached the sensorium through the means of the circulation. 
These are important facts, and due weight will hereafter be 
yielded to them. Give to an animal that has undergone this 
operation the usual dose of emetic tartar or of aloes, and they 
produce not, at the usual period, and oftener not at all, their 
usual effects. These are striking illustrations of Dr. Marshall 
Hall’s excito-motory system of nervous influence. He considers 
these nerves as simply excito-motory. The impression made on 
them is conveyed to the medulla oblongata, thence propagated 
to the brain, after which the appropriate muscles are set at work. 
If the nerves are divided, the impression cannot be transmitted 
to the brain — no mandate can be issued, and no effect is pro- 
duced. The failure, however, in the action of medicines, and in 
the discharge of many of the duties of this portion of the system, 
may depend on one of two causes, and a little on both of them. 
There may be comparative insensibility of the stomach, or 
want of power in the spinal organic nerves to transmit certain 
impressions, or there may be insensibility in the cerebral system 
to receive and respond to the warnings that are conveyed. They 
are both dangerous pathological states, and it behoves the prac- 
titioner anxiously to inquire into the matter, and to apply the sti- 
mulus, or occasionally the sedative, in the proper quarter. Disease 
in the one may, and in a thousand cases does, derange the functions 
of the other. No two organs are, in a pathological point of view, 
so closely connected. You are now, perhaps, beginning to see 
a little the reason of this. In no two organs is it, occasionally, 
so difficult to detect which is in fault — which is the injurious 
agent, and which the victim. But I check myself : neither you 
nor I are yet prepared for these speculations. 
The Stomachs of Ruminants . — These organs afford the most 
interesting manifestations of the motor power of the nerves of 
the stomachs. Consider the bulk of the rumen, and, after a 
hearty meal, the weight of its contents. I need not tell you 
that, after the process of rumination, it is never more than half 
emptied of its contents ; and when that process again commences, 
it weighs twenty or thirty or forty pounds. How powerful must 
be the muscular action, and the nervous influence, to agitate a 
mass like this, and to bring every portion of it in its turn into 
