COMPARATIVE DIGESTION. 119 



eggs, milk, and many other substances susceptible of being 

 converted into nutriment, are speedily reduced to coagu- 

 la, after which they are entirely dissolved by the gastric 

 juice. The effects and design of this provision is, to 

 retain the aliment 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 mat- 

 ter, though ever so nutritive in its qualities, the nourish- 

 ment 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 dis- 

 solved. 



Dr. Hunter ascertained that this coagulating property 

 belongs to the gastric fluid of every animal he examined 

 for this purpose, from man down to the reptiles. 



Experiments on the digestibility of different kinds of 

 aliment will be found in another place. 



COMPARATIVE DIGESTION. 



The human stomach, as we have seen, is exceedingly 

 simple in its construction, consisting merely of a single 

 sac with two apertures. 



The corresponding part of herbivorous animals con- 

 sists 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 

 impressive examples of Creative design, any where to 

 be found in animal structures. 



Stomach of a Sheep. The delineation, Fig. 80,repre- 



What is said to be the most obvious property of the gastric juice 1 

 What is said concerning fluid nutriment ? 



