292 Food, 



formation of chyme is owing to the stomachy but that the conversion 

 of food into this pappy mass, is effected by means of a particular 

 fluid which is separated from the blood, by the arteries of that organ, 

 and has obtained the name of gastric juice. For, the experiments 

 of Spallanzani, made about thirty years ago, which Doctor Stevens 

 and other English philosophers, have since repeated with the same 

 results, prove, beyond all dispute, that some substances, which would 

 remain unaltered for weeks or months, though kept in a temperature 

 equal to that of the living body, are digested in the course of a few 

 hours, in the stomach of a dog, or any other carniverous animal, by 

 the action of the gastric juice alone. For, the first ingenious Philo- 

 sopher, having enclosed pieces of solid bone, in hollow cylindrical 

 tubes, that were perforated, and afterwards introduced into the sto- 

 mach of a dog, found that the bone was completely dissolved, that i^ 

 to say digested, whilst at the same time, the tubes on being voided^ 

 were found to have retained their cylindrical form. And if any 

 one should be desirous of being furnished with proof still more 

 convincing, that digestion is effected solely through the medium 

 oi a fluidj in the stomach, it is only necessary to add, that if the 

 same substances which were found to be digested in tubes that 

 were perforated, were inclosed in such as were imperforate, they 

 were found, on the tubes being voided, to have unilergone no other 

 change, than that which would have taken place in the same temper- 

 ature, out of the living body. Putting these facts together, it must 

 be evident, therefore, that neither mechanical force, nor fermentation 

 in the stomach, can have any thing to do with the digestive process. 

 For, if the first were the cause of digestion, then the tubes must 

 have been crushed to pieces, before the bone could have been ground,, 



