582 DIGESTION. 



a wound of the abdomen has shown, that the compression exerted by it 

 on its contents is totally insufficient to bruise any resisting substance. 

 Moreover, we constantly see fruits, as raisins and currants, passing 

 through the whole intestinal canal unchanged ; whilst worms remain in 

 the stomach reside there unhurt ; and, we shall see presently, that 

 the experiments of Re'aumur and Spallanzani proved most convincingly, 

 that digestion is effected independently of all pressure. The futility, 

 indeed, of this mode of viewing the subject is signally illustrated by 

 the fact, that, whilst Pitcairne estimated the power of the muscular 

 fibres of the stomach at 12,951 pounds, Hales 1 thought that twenty 

 pounds would come nearer the truth ; and Astruc 2 valued its compressive 

 force at five ounces ! 



4. Fermentation. The system of fermentation had many partisans; 

 amongst whom may be mentioned Van Helmont, 3 Sylvius, 4 Willis, 5 

 Boyle, 6 Grew, 7 Charleton, 8 Lower, 9 Raspail, 10 &c. Digestion, in this 

 view, was ascribed to the chemical reaction of the elements of the food 

 during their stay in the stomach ; the action being excited by food 

 that had already undergone digestion, or by a leaven secreted for the 

 purpose by the stomach itself. In favour of this view, it was attempted 

 to show, that air is constantly generated in the organ, and that an acid 

 is always produced as the result of fermentation, the formation of 

 chyme being referred by the greater number of physiologists to the 

 food undergoing the vinous and acetous fermentations. The objections 

 to this doctrine of fermentation are ; that digestion ought to be totally 

 independent of the stomach, except as regards temperature ; and the 

 food ought to be converted into chyme, exactly in the same manner, 

 if it were reduced to the same consistence, and placed in the same tem- 

 perature, out of the body; which is not found to be the case. Bones 

 are speedily reduced to chyme in the stomach of the dog, although they 

 would remain unchanged for weeks, in the same temperature, out of the 

 body. The facts of the voracious fishes before mentioned likewise prove 

 the insufficiency of the hypothesis ; according to which, digestion ought 

 to be accomplished as effectually in the oesophagus as in the stomach. 

 Yet it is found that, whilst the portion in the stomach is digested, the 

 other may be unaltered, or be putrid. The truth is; in healthy diges- 

 tion, fermentation, in the ordinary acceptation of the term, does not 

 occur; and, whenever the elements of the food react upon each other, 

 it is an evidence of imperfect digestion; hence, fermentation is one of 

 the most common signs of dyspepsia. , 



5. Chemical solution. The theory of chemical solution, proposed by 

 Spallanzani, 11 and subjected to modifications, has met with more favour 



1 Statical Essays, ii. 174, 4th edit., Lond., 1769. 



2 Traite de la Cause de la Digestion, &c., Toulouse, 1714; and Haller, loc. citat. 



3 Ortus Medicinse, &c., Arnstel., 1648. 4 Opera, Genev., 1781. 



5 Diatribae duae Medico-Philosophicse. &c., Lond., 1659. 



6 Works, vol. ii., Lond., 1772. 



7 Comp. Anat. of the Stomach, &c., Lond., 1681. 8 (Econ. Anim. Exerc. 2. 



9 Tractatus de Corde, &c., Amstel., 1671. 



10 Chimie Organique, p. 356, Paris, 1833. 



11 Dissertations relative to the Natural History of Animals and Vegetables : sect.!., Lond., 

 1789. 



