NATURE OF CHYMIFICATION. 503 



4. Nature of Chymification and Chylification. 



663. The causes of the reduction of the food in the Stomach, have long 

 been a fruitful source of discussion amongst physiologists ; and various hy- 

 potheses have heen devised to account for it. Some have compared the Sto- 

 mach of Man to the Gizzard of a fowl, and have supposed that the trituration 

 of the food between its walls was the essential element in the process ; but 

 this doctrine is completely incompatible with the fact, that digestible substances, 

 inclosed in metallic balls with perforations in their sides, are still dissolved by 

 the power of the gastric fluid, though the walls of the stomach do not come 

 in contact with them. Others, again, have imagined that the process of di- 

 gestion is one of putrefaction ; but this idea, putting aside its inherent ab- 

 surdity, is proved to be incorrect by the fact that the gastric juice has a de- 

 cidedly antiseptic quality. Others, in despair of obtaining any other solution, 

 have attributed the operation to the direct agency of the vital principle ; for- 

 getting that, as long as the aliment remains within the stomach and intestinal 

 canal, it can no more be the subject of any peculiarly vital process, than if it 

 were in contact with the skin, of which the mucous membrane is but an inter- 

 nal reflexion. The theory of chemical solution, which was at first regarded 

 by many as quite untenable, has been of late years so much strengthened by 

 new facts and arguments, that there now appears no valid reason for with- 

 holding our assent from it; even though it cannot yet give a complete expla- 

 nation of the complex phenomena in question. The chief opposition to this 

 theory has arisen from the difficulty of imagining, that any simply-chemical 

 solvent should have the power of acting on so great a variety of substances, 

 and of reducing them to a state so homogeneous. This difficulty, however, 

 seems now in a great degree removed, by the discovery of the close Chemical 

 relation that subsists, between the various substances of each of the groups 

 already enumerated ( 639) ; which renders it easy to conceive, that the 

 changes involved in their reduction may be of a very simple character. 



664. The first series of facts which will be here adduced, as throwing light 

 on the process of Chymification, is that which has been obtained by the ex- 

 periments of Dr. Beaumont upon the individual already alluded to ( 658.) 

 By introducing a tube of India-rubber into the empty stomach, he was able 

 to obtain a supply of Gastric Juice whenever he desired it ; for the tube 

 served the purpose of stimulating the. follicles to pour forth their secretion, 

 and at the same time conveyed it away. This fluid, of which the existence 

 has been denied by some physiologists, is not very unlike saliva in its appear- 

 ance ; it is, however, distinctly acid to the taste ; and chemical analysis shows 

 that it contains a considerable proportion of free muriatic acid, and also some 

 acetic acid. The former must evidently be derived from the decomposition 

 of the muriate of soda contained in the blood, the remote source of which is 

 the salt ingested with the food. The latter is an organic compound, probably 

 formed at the expense of some of the saccharine matter of the previous ali- 

 ment. Of equal importance with the free acids, is an animal matter, soluble 

 in cold water, but insoluble in hot, bearing considerable resemblance to albu- 

 men. Of this more will be said hereafter. Besides these principal ingre- 

 dients, the gastric fluid contains muriates and phosphates of potass, soda, 

 magnesia, and lime. It possesses the power of coagulating albumen in an 

 eminent degree ; it is powerfully antiseptic, checking the putrefaction of meat ; 

 and it is effectually restorative of healthy action, when applied to old fetid 

 sores and foul ulcerating surfaces. It may be kept for many months, if ex- 

 cluded from the air without becoming fetid. 



a. The Chemistry of the Gastric Juice has been greatly unsettled by the results of recent 



