DIGESTION. 



17 



not acted upon, thus proving decisively that 

 the effect was not produced by a mere mecha- 

 nical operation.* The results of these experi- 

 ments have been confirmed by some remark- 

 able facts, which bear still more directly upon 

 the point under investigation, where certain in- 

 dividuals have had preternatural openings made 

 into the stomach, either from accident Or dis- 

 ease, while the functions of the part appear to 

 have been but little, if at all, impaired. By 

 this means the operation that is going forwards 

 in this organ may be minutely watched in all 

 its various stages, and we are enabled to ob- 

 serve the change which the food undergoes 

 from the time that it enters the stomach until 

 it passes from the pylorus, and to compare the 

 changes which the different kinds of food ex- 

 perience during the progress of the whole mass. 



A case of this kind is related by Circaud, 

 where an individual lived many years with a 

 fistulous opening into the stomach ;f but a 

 much more remarkable case of the same de- 

 scription has been lately communicated by Dr. 

 Beaumont. The individual in question was 

 wounded, early in life, by a shot in the epigas- 

 tric region, which perforated the stomach. 

 After some time the wounded part healed, 

 with the exception of an aperture two and a 

 half inches in diameter, which communicated 

 with the stomach. He lived many years in 

 this state, in perfect health and vigour, so as to 

 be capable of following a laborious occupation, 

 while the fistulous opening still remained. 

 Under these circumstances he was made the 

 subject of experiment by Dr. Beaumont, who 

 for the space of eight years continued his ob- 

 servations, with great assiduity and minuteness, 

 on the action of the stomach both in its ordi- 

 nary state, and when subjected to different con- 

 ditions, for the immediate purpose of the expe- 

 riment. We may remark generally, that the 

 results of the experiments confirm those of 

 Spallanzani in their most essential particulars, 

 and at the same time enable us to decide upon 

 some points which were left imperfect by that 

 naturalist.^ 



Among the more important points respecting 

 the formation of chyme, which appear to be 

 confirmed by the experiments of Dr. Beau- 

 mont, are the following; that the different 

 kinds of aliment all require to undergo the 

 same process, by means of the gastric fluid, 

 i order to be reduced into chyme ; that the 

 rapidity of the process differs considerably 

 according to the delicacy of their natural tex- 

 ture or the degree of their mechanical division ; 

 that the saliva is of no specific use in the con- 

 version of aliment into chyme; that animal 

 substances are more easily converted into 

 chyme than vegetables; and that oily sub- 

 stances, although they contain a large quantity 



* Reaumur, Med. Acad. pour 1752, p. 266 et seq. 

 and p. 461 et seq. ; Stevens, De Alim. Concoct, 

 cap. xii. ex. 1 ... 9 and 11 ... 23 ; Spallanzani, 

 Exper. sur la Digest, passim ; Blumenbach, Inst. 

 Physiol. $358,9; Monro(Tert.)Elem.v.i. p. 532. 



t Journ. de Phys. t. liii. p. 156, 7. 



$ Beaumont on the Gastric Juice and on Diges- 

 tion, sect. 1, 5. 



VOL. II. 



of nutriment, are comparatively difficult of 

 digestion.* 



We must next inquire into the physical and 

 chemical properties of the gastric juice, the 

 fluid secreted from the interior of the stomach, 

 by which the change in the aliment, that we 

 have been describing, is produced. Since the 

 publication of Reaumur's experiments, about 

 the middle of the last century, the general 

 opinion among physiologists and chemists has 

 been, that the gastric juice possesses specific 

 properties, which enable it to dissolve or com- 

 bine with the aliment ; and many experiments 

 have been performed for the purpose of ascer- 

 taining the chemical nature of the secretion, 

 so as to account for the powerful action which 

 it appears to possess over such a great variety 

 of substances. Besides the more general ac- 

 count which we have of the gastric juice by 

 Boerhaave, Haller, and Reaumur,f it was made 

 the subject of an elaborate series of expe- 

 riments by Spallanzaui;J it was also analyzed 

 by Scopoli and by Carminati,|| and has been 

 lately examined by Dr. Prout,^[ and by MM. 

 Tiedemann and Gmelin.** The result is, upon 

 the whole, rather unsatisfactory, or at least it 

 may be said, that nothing has been detected 

 in the fluid, which seems to account for or 

 explain the powerful action which it exercises 

 on the alimentary substances subjected to its 

 influence.-)-! All that we learn is, that the 

 gastric juice contains certain saline substances 

 in small quantity, more especially the muriate 

 of soda, in common with the other animal 

 fluids, but that it does not differ essentially, 

 in its chemical properties, from saliva, or from 

 the secretions of mucous membranes gene- 

 rally. Dr. Prout indeed informs us, that a 

 quantity of muriatic acid is always present in 

 the stomach during digestion ;JJ but as there 

 does not seem to be any decisive evidence of its 

 appearance previously to the introduction of 

 the food into the stomach, we ought probably 

 rather to consider it as developed by the pro- 

 cess of digestion, than as entering into the 

 constitution of the gastric juice; nor indeed, 

 if it were so, are we able to explain the mode 

 in which it operates in converting aliment into 

 chyme. This apparent difficulty in account- 

 ing for the mode in which chyme is formed by 

 the gastric juice, and the supposed inadequacy 



* Beaumont, page 275 . . 8 et alibi. 



t Boerhaave, Praelect. 77 et seq. ; Haller, El. 

 Phys. xix. 1. 15. et 4. 20: Reaumur, Mem. Acad. 

 pour 1752, p. 480, 495. 



t Ut supra, $ 81 et seq. 145, 185, 192. 



In Spallanzani, 244. 



|| Jour. Phys. t. xxiv. p. 168 et seq. 



IT Ann. Phil. v. xiii. p. 13. 



** Recherches sur la Digestion, trad, par Jour- 

 dan. 



ft Henry's Chem. v. ii. p. 410, 1. 



ft Phil. Trans, for 1824, p. 45 et seq. 



The presence of acid in the stomach, in its 

 healthy state, has been made the subject of in- 

 quiry by many experimentalists, and of much con- 

 troversy ; the result is that the older physiologists 

 generally denied its existence, except in morbid 

 states of the stomach, while many of the most 

 eminent modern physiologists believe it to be 

 always present, and indeed regard it as an essen- 



C 



