COMPARATIVE DIGESTION. 115 



oggs, milk, and many other substances susceptible of being 

 converted into nutriment, are speedily reduced to coagula, 

 after which they are entirely dissolved by the gastric juice. 

 The design and effects of this provision is, to retain the ali- 

 ment in the stomach a sufficient length of time to be 

 thoroughly acted upon by its digestive power. For it has 

 been ascertained by experiment, that if the aliment consists 

 of too large a proportion of fluid matter, though ever so 

 nutritive in its qualities, the nourishment it affords will be 

 but small in quantity, especially if the fluid be incapable of 

 coagulation, because it passes beyond the stomach before 

 it is fully digested or dissolved. 



333. Dr. Hunter ascertained that this coagulating prop- 

 erty belongs to the gastric fluid of every animal he exam- 

 ined for this purpose, from man down to the reptiles. 

 Experiments on the digestibility of different kinds of ali- 

 ment will be found in another place. 



COMPARATIVE DIGESTION. 



334. The human stomach, as we have seen, is exceed- 

 ingly simple in its construction, consisting merely of a sin- 

 gle sac, with two apertures. 



335. The corresponding part of herbivorous animals 

 consists of a far more complex apparatus, being composed 

 of four distinct sacs or stomachs, communicating with each 

 other, and exhibiting as a whole, one of the most impres- 

 sive examples of creative design, anywhere to be found in 

 animal structures. 



336. Stomach of a Sheep. The delineation, Fig. 80, 



Fig. 80. 



What is said to be the most obvious property of the gastric juice ? What 

 is said concerning fluid nutriment ? 



