STRUCTURE AND OFFICE OF THE STOMACH. '"^ 



These secretions are ascertained by Dr. Steveae's experi- 

 ments to have a solvent power in a slight degree, since 

 vegetable substances contained in tubes were dissolved in 

 the paiinch of a sheep*. 



The food thus mixed is returned into the mouth, where Second stage. 

 it is masticated by the grinding teeth ; it is then conveyed 

 into the third cavity, in which it would appear from the 

 gasf let loose, that a decomposition takes place, and 

 thence it is received into the upper portion of the fourth 

 cavity. 



The changes which are produced on the food in the first The4thstG- 

 three cavities are only such as are preparatory to digestion, "^^ } ?. '™* 

 and it is in the fourth alone this process is carried on. In tion, 

 the plicated portion the food is acted on by the secretion of 

 the solvent glands ; and in this portion of the cavity of the 

 deer's stomach small orifices are seen in the internal mem- 

 brane leading to cavities, the size of a pin's head, which I 

 consider to be the openings of these glands, since they bear Formation of 

 some resemblance to those of other stomachs. In the lower pie,ej^- ^ ^°^ 

 portion the formatiou of chyle is completed. lower portion. 



In birds with gizzards the food goes through very similar Birds -with gb- 

 changes; it is picked up by the bill, which in smaller birds ^"^*- 

 separates the hcsk from the seed, it then passes into the 

 crop, where it is acted on by the secretions of that caivity, 

 after which it is received into the gizzard, to undergo the 

 same change produced by the grinding teeth of the rumi- 

 nants j the secretion of the solvent glands is then poured 

 upon it, acting upon the nutritious part before it is spread 

 upon the glandular structure at the orifice of the gizzard, in 

 which last situation it is formed into chyle. 



In the whale tribe, the first cavity, although lined with Whale tribe, 

 a cuticle, has secretions peculiar to it, and therefore cor- 

 responds with the first and second of the ruminants, and 

 with the crops of birds with gizzards: it answers however a 



* Dissertaiio Pkysiologica inau^uralis de Alinentorum concoctione, Au- 

 /•re Edwardo Stevens, Edinb. 1777. 



+ Mr Davy and Mr. W. Brande examined this gas, and found it to be Not the fer- 

 inflammable, and not to contain carbonic acid; which establishes adif mentatjve pro- 

 iferencc belweep this process and fermentation. *^"*' 



farther 



