300 Medicine, [Chap. IV, 



ill medical science was desirous to explain diges- 

 tion on mechanical principles. 



Early in the eighteenth century Mr. Cheselden 

 appears to have imbibed some correct notions on 

 this subject. He remarked, that in serpents, some 

 birds, and several kinds of fishes, digestion seemed 

 to l"3 performed by some unknown menstruum ; as 

 he frequently found in their stomachs animals so 

 totally digested, before their form was destroi/ed, 

 that their very bo7ies were rendered soft. 



About the same time M. Reaumur instituted 

 a set of experiments concerning this function ; 

 and, by a number of clear and decisive facts, ex- 

 hibited in his excellent memoirs on this subject, 

 proved the existence and agency of a solvent in 

 the stomach. 



About the year 1777> the abbe Spallanzani, 

 professor of natural history in the university of 

 Pavia*, began, by his numerous experiments and 

 diversified inquiries, to throw new light upon the 

 function of digestion. Having directed his inqui- 

 ries to a great number of animals, man, quadru- 

 peds, birds, fishes, and amphibia, he was led to 

 divide an extensive variety of stomachs, differing 

 from one another in many important points of 

 structure and functions, into three classes, the 

 muscular, inter mediate y and membraiious f. 



* The abbe Lazarus Spallanzani,of Italy, was bom in the year 

 1729, and died in 1800. His researches and publications in seve- 

 ral branches of natural history, especially in animal and vegetable 

 physiology, place him among the most distinguished men of his 

 age. On the subject of Bigcslion, he is, perhaps, the highest 

 authority. 



t Dissertations relative to the Natural JJiitojy of Ammah and 

 Vtgetabk's, vol. i. 



