OF I'NEUMO-GASTRIC NE&VES IN DIGESTION. $fi 



lowing that the stomach derives its chief and its more vital influence from the ganglial 

 system, and an additional and a modified influence from the cerebro-spinal system, the 

 latter exciting- or otherwise influencing the former, and granting that respiration is re- 

 quisite to the energy of both, it surely cannot be for a moment doubted, that an 

 interruption either of the one or the other should occasion, owing both to the 

 defect of a requisite influence and to the injury done to the system generally by 

 the experiment, a very considerable derangement of the functions of this organ. We 

 perceive that slighter causes, such as those mentioned at p. 77 of the text, will produce 

 a much greater disorder of the actions of the stomach than the formidable operation of 

 division of the eighth pair of nerves formidable not only as respects its effects upon 

 digestion, but as regards its influence on the function of respiration, and upon the body 

 generally can it therefore be a matter of surprise, that destruction of, or interruption 

 to, a wonted and requisite influence should be followed by marked effects upon the 

 organ which such influence is destined to actuate ? Because the influence conveyed 

 by the nerves from the cerebro-spinal sysem affects the functions of the stomach or 

 an interruption to it disorders them, can it therefore be logically concluded that this 

 viscus derives its functions from that source, and that none of them acknowledges any 

 other origin ? Because these particular nerves are ready conductors of galvanism, and 

 because galvanism excites the. natural actions of the digestive organs, ought it therefore 

 to be concluded, that the natural office of these nerves is to convey and distribute this 

 agent, or that the vital influence with which these organs are endowed, is identically 

 the same as it ? We think that no one can be justified in answering these questions in 

 the affirmative, by the evidence which these experiments afford. From a careful con-, 

 tnderation of the phenomena which they furnished, and from the few experiments 

 \vhich we have made with this active agent, we conclude, 1st.- That the functions of 

 the stomach depend chiefly upon the supply of ganglial nerves, which its vessels, mus- 

 cular fibres, and secreting surface receive. 2d. That the pneumo-gastric nerves con- 

 vey the influence of the cerebro-spinal system to this organ, which influence re-inforces 

 that which it receives from the ganglial system, or proves a stimulus to it. 3d. That 

 this latter influence is more requisite to the perfect performance of the functions of 

 the stomachj the older the animal is, and the higher we rise, in our observations 

 amongst the more perfect animals. 4th. That when this influence is interrupted, in a 

 more or less complete manner, in its course to the stomach, its place may be, in some 

 measure, supplied by galvanism, which seems to excite the proper or vital influence 

 which the organ receives from the ganglial system. 5th. That we have no proof of 

 galvanism acting otherwise in the process than as a stimulus to properties already pos- 

 sessed by the organ on which it acts, and that it acts in those experiments through a 

 medium to which the organ is habituated, and in a great measure dependent for a na- 

 tural excitement. 6th. That although galvanism excites the functions of the stomach, 

 for a time, we have no evidence of its continued power in promoting them, during a 

 protracted interruption of either the one species of nervous influence or the other; it 

 even appears probable that the continued operation of this agent, although like other 

 powerful stimuli it at first actively excites the natural functions of the part on which 

 it acts, would, nevertheless, exhaust them, more especially if they were not supplied 

 from their natural sources. 7th. That, as we have no comparative trials of the effects 

 of other powerful stimuli, under similar circumstances to those in which galvanism has 

 been employed, conclusive inferences cannot be drawn respecting the extent of influ- 

 ence of that agent ; at least none that can oppugn the above positions, they may, and, 

 very probably, they will confirm them, and show that the activity of galvanism in exci- 

 ting the animal operations, merely results from the properties of this agent enabling it 

 to act, through channels which convey a natural and a requisite influence, in a more 

 energetic manner than other excitants which we can employ in our experiments. Rea* 

 soning, indeed, from what we already know of the properties of galvanism, and from 

 its operations upon inorganized matter, we should be led to expect more energetic ef- 

 fects from it upon the animal system, than from any other agent which we have under 

 our control. 



