596 DIGESTION. 



portion to the time .that had elapsed from the period of chymification, 

 or of filling the stomach. M. Longet thinks, that these facts account 

 for the different results arrived at by experimentalists in regard to the 

 influence of the pneumogastric nerves over the movements of the 

 stomach; for, if the same experiments were made when the stomach 

 was in different states, they might readily lead to opposite conclusions. 

 He was never able to excite any movement of the coats of the stomach, 

 by irritating or galvanizing the filaments of the great sympathetic or 

 the semilunar ganglia. 



On the whole, the proposition of Dr. Philip, that if the eighth pair 

 be divided in such a manner as to effectually intercept the passage of 

 the nervous influence, digestion is suspended, is generally considered 

 to be established; although it must, we think, be admitted with Mr. 

 Mayo, 1 that the rationale of the subject remains involved in great un- 

 certainty. Like other secretions, that of the gastric juice, although 

 capable of being modified by the nervous influence, cannot be regarded 

 as immediately dependent upon it. The secretion, of the true acid cha- 

 racter and solvent powers, is not always checked by the section of the 

 nerves, and the experiments of Dr. John Reid 2 and others have suffi- 

 ciently shown, that the integrity of those nerves is not a condition 

 absolutely necessary for secretion in the stomach, whilst at the same 

 time they prove, that the amount of secretions usually poured into the 

 interior of that organ may be modified in an important manner by causes 

 acting through those nerves. 3 It". is denied, however, by Professor J. 

 Muller, that galvanism has any influence in re-establishing the gastric 

 secretion, when it has been checked by their division. 



Finally: Dr. Philip found, that every diminution of the nervous 

 influence, the section of the medulla spjnalis at the inferior part, for 

 example, deprives the stomach of its digestive faculty; and MM. 

 Edwards and Vavasseur obtained the same result by the removal of a 

 certain portion of the hemispheres of the brain, or by the injection of 

 opium into the veins in sufficient quantity to throw the animal into 

 deep coma. Much must, of course, be dependent on the deranging 

 influence of the experiments. By means of the fistulous openings into 

 the stomachs of dogs, first instituted by M. Blondlot, (see page 586,) M. 

 Bernard 4 undertook fresh experiments on this unsettled topic. A dog's 

 digestion was watched for eight days, and found to be well accomplished. 

 On the ninth day, after twenty-four hours' fast, M. Bernard sponged 

 out the stomach, which contracted on the contact of the sponge, and 

 at once secreted a large quantity of gastric fluid. He then divided 

 the pneumogastric nerves in the middle of the neck, and immediately 

 the mucous membrane, which had been turgid, became pale, as if 

 exsanguious; the movements of the stomach ceased; the secretion of 

 gastric fluid was instantaneously arrested, and a quantity of neutral 

 ropy mucus was soon produced in its place. After this, digestion was 



1 Outlines of Human Physiology, 4th edit., p. 122, Lond., 1837. 



2 Edinb. Med. and Surg. Journal, April, 1839; and art. Par Vagum, in Cyclop, of Anat. 

 and Physio!., pt. xxviii. p. 899, Lond., April, 1847. 



3 Longet, Traite de Physiologic, ii. 339, Paris, 1850. 



4 Gazette Medicale de Paris, 1 Juin, 1844. 



