THE BUNCTIONS OF THE VISCERAL NERVES 97 
expulsion of urine very frequently seen in the lower animals in consequence 
of fear, and the temporary palsy of the detrusor often witnessed in the human 
subject in surgical practice as the result of severe injury, seem to me to imply 
that the bladder, too, while sometimes stimulated through the cerebro-spinal 
axis, 1s paralysed by its very powerful operation. Hence it seems probable that 
the movements of all the hollow viscera are liable to similar influence from the 
spinal system. At the same time it appears to be a mistake to regard this 
influence in the light of a strict control; for the experiments related in this 
letter show pretty distinctly that the contractions of the heart and the peristaltic 
action of the intestines are regulated, under ordinary circumstances, by the 
independent operation of the intrinsic ganglia. 
Professor Schiff has, I understand, observed increase of the heart’s action 
to result from very gentle stimulation of the vagus,! and has come to the con- 
clusion, as stated by Spiegelberg in his paper before referred to, that the inhibit- 
ing influence depends upon nervous exhaustion. There are some circumstances 
which make me entertain great doubt as to the correctness of this view. In 
the first place, the very rapid recovery of the cardiac or intestinal actions when 
the inhibiting galvanic currents are discontinued, contrasts strongly with the 
length of time that the impairment of function resulting from a protracted 
experiment, and certainly due to exhaustion, lasts both in the intrinsic cardiac 
nerves and in those that connect them with the spinal system. Secondly, 
although very powerful galvanism not only arrests for the time, but permanently 
impairs the action of the heart, no such effect is observed to follow the inhibiting 
influence when it is caused by milder stimulation ; indeed, according to my 
experience, less injurious effects are produced upon the heart by a protracted 
series of experiments of the latter kind than by a corresponding set with the 
currents still more feeble, that increase, while acting, the frequency of the 
contractions. But if the diminished rate of the pulsations were caused by 
a partial exhaustion of the cardiac ganglia, an opposite result might have been 
anticipated. 
Again, there can be little doubt that dilatation of the blood-vessels, in 
consequence of a stimulus, is due to an effect produced upon the nervous centres 
for the arteries, similar to that experienced by the visceral ganglia when subject 
to the inhibiting influence. Now an inflammatory blush of long continuance 
may subside rapidly when the source of irritation is withdrawn. Thus I have 
seen redness which had existed for about three days in the human skin in con- 
sequence of tight stitches connecting the lips of a wound, give place at once 
to pallor on their removal. Had the arterial dilatation in this case been the 
* Henle and Meissner’s Bericht, 1857. 
LISTER I H 
