THE BUNCHIONS OF THE VISCERAL NERVES 89 
of the nervous apparatus concerned were in a less active condition, no doubt 
in consequence of exhaustion. The arches of the tenth and eleventh dorsal 
vertebrae having been removed before the experiments with galvanism, I sub- 
sequently introduced a fine needle into the exposed part of the cord, with the 
effect of causing in repeated instances increased movements of the intestines, 
which were especially striking on account of the occurrence of peculiar local 
contractions not seen at other times. Further observations upon this animal 
tended to confirm those which have been mentioned, as did an experiment 
of the same kind performed the next day upon another rabbit. 
I afterwards found that the best mode of proceeding was to remove the skin 
and one or two layers of muscles from a portion of the abdomen till the parietes 
were sufficiently thinned to permit the intestines to be distinctly seen through 
them ; by this means the complication produced by exposure of the intestines 
to the atmosphere was avoided, and the most satisfactory results were obtained ; 
the increase of the peristaltic movements during the transmission of extremely 
feeble shocks being strikingly apparent and constant on every occasion. During 
the experiment performed in this way I noticed several times that a violent 
struggle on the part of the rabbit, when the intestines were in pretty free move- 
ment, was followed by absolute and universal quiescence of those organs for 
several seconds; this appeared to me of great interest, as proving that the 
inhibitory influence is certainly sometimes exerted in the natural actions of 
the animal, and is.not merely the result of artificial stimulation. 
In the course of the above experiments several other observations were 
made. In the first place I verified the statement of Pfliiger, that if, when the 
intestine is lying relaxed under the inhibiting influence of galvanism applied 
to the spine, a particular part be irritated, local contraction occurs, but is not 
propagated to neighbouring parts. This fact is of fundamental importance, 
since it proves that the inhibitory influence does not operate directly upon 
the muscular tissue, but upon the nervous apparatus by which its contractions 
are, under ordinary circumstances, elicited. 
Another point which seemed to require investigation was the well-known 
increase of peristaltic action which takes place after death, and which continues 
in spite of cutting off the mesentery close to the gut. Those who believe in 
a constantly restraining function of certain nerves during life might argue that 
the intestine has always a tendency to such active movements, but is kept 
in check by the ‘inhibitory nerves’, and released from their control when 
they have lost their power after death. A different explanation, first suggested, 
I believe, by Bernard, is that the increased action of the intestines is the result 
of failure of the circulation in the part ; and to this view I felt disposed to agree, 
