240 Medicine, 



Spallanzani's next experiments were directed 

 to animals possessing what he called intermediate 

 stomachs ; such as are endowed with muscles less 

 thick and strong than the former, but more so 

 than the membranous stomachs. Among these he 

 examined and made experiments upon the -raven, 

 the crow, the heron, and many other birds, which 

 have this intermediate structure of the organ in 

 question. It was found in these birds, as might 

 be expected, that digestion is performed by a more 

 equal combination than in the former cases, of 

 the forces of muscular action and a gastric men- 

 struum secreted for the purpose. 



These interesting experiments on digestion were 

 finished with those animals which have thin mem^ 

 hranous stomachs. This class comprehends an 

 immense number of species, as man, quadrupeds, 

 fishes, reptiles, &c. No triturating power is pos- 

 sessed by the stomachs of this description ; for their 

 muscular fibres seem to exert little other effect 

 than that of propelling their contents through the 

 pylorus. In proof of this is alleged the well 

 known fact that cherries and grapes are often re- 

 ceived and voided entire from the human alimen- 

 tary canal. The solvent power of the gastric 

 liquor, in these animals, was found almost solely to 

 effect the dissolution of food, after the preparatory 

 treatment of mastication, and the admixture of 

 saliva. To prove the efficacy of this powerful agent 

 in the process of digestion, Spallanzani enclosed 

 different kinds of animal and vegetable food in 

 linen bags, and in wooden tubes, perforated in such 

 manner as to admit the entrance of the gastric juice; 

 these he swallowed himself, and, after a short in- 

 terval, the contents of them were found to be dis- 

 solved and discharged. Me satisfied himself that no 

 trituration could take place by employing tubes 

 so thin and weak that the slightest pressure would 



