379 



to imply that the bladder, too, while sometimes stimulated through 

 the cerebro-spinal axis, is 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 conclusion, as stated by Spiegelberg in his paper before 

 referred to, that the inhibiting influence depends upon nervous 

 exhaustion. There are some circumstances which make me enter- 

 tain 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 cor- 

 responding set with the currents still more feeble, that increase, 

 while acting, the frequency of the contractions. But if the dimi- 

 nished rate of the pulsations were caused by a partial exhaustion 

 of the cardiac ganglia, an opposite result might have been antici- 

 pated. 



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 



* Henle and Meissner's Bericht, 1857. 



