STOMACH OF BIRDS. 



499 



transatlantic wilds, subsists entirely on plants for three-fourths of the 

 year, and in a domestic state requires no other food. 



It is true both the turkey and the goose greedily devour grain, and 

 various other seeds occasionally, and appear to prefer it ; and, conse- 

 quently, we may reasonably conclude, nature has given them both mus- 

 cular gizzards, not for the purpose of grinding herbaceous food, but to 

 triturate and comminute substances that may occasionally offer them- 

 selves, and which must otherwise cause a stoppage, or pass off undi- 

 gested, as corn is commonly observed to do with horses, if it is not 

 broken by the grinding teeth. 



Had this anatomical writer examined the stomach of a truly grami- 

 nivorous bird, we have no doubt he would not have considered that a 

 superior muscular strength in the stomach was necessary for the com- 

 minution of herbaceous food, since (as we have noticed) the stomach 

 of the little bustard appears to be divested of sufficient muscular action 

 to comminute its food by compression. From the structure of the sto- 

 mach of this bird, which is one of the very few that is truly grami- 

 nivorous, we are naturally led to conclude, that the leaves and tenderer 

 parts of plants are readily macerated, and prepared in the stomach, by 

 the conjoint action of the gastric juice and the animal heat, more than 

 by friction. The vast distention of the stomach in this bird, charged 

 with such a large quantity of herbaceous food, rendered it impossible 

 for the coats of the stomach to come sufficiently near to perform attri- 

 tion ; nor were there any gravel stones perceived, to assist such action. 

 May we not, therefore, fairly infer, that grass and other herbs are, 

 under certain circumstances, rendered easy of digestion, and yield their 

 utmost possible nutriment without trituration in the stomach? The 

 stomach of the little bustard is not furnished with that strong carti- 

 laginous substance apparent in more omnivorous birds, and, in parti- 

 cular, those who occasionally feed on grain and other hard substances, 

 that require breaking and comminuting by strong muscular pressure 

 and friction ; but is more analogous to that of carnivorous birds, except 

 that it is vastly superior in size. The stomach of the capercalzie 

 (Tetrao urogallus,) and other species of the same genus we have 

 examined, are very similar to that of the turkey ; and these feed prin- 

 cipally on the tops of heath, birch, pine, and other green vegetables ; 

 but as these are not tender, but of a ligneous quality, their stomachs 

 are always found to contain a large portion of gravel, or grit, in order 

 to facilitate the comminution of their food. 



Why grass and other green vegetables should not be dissolved or com- 

 minuted in the stomach of carnivorous birds and quadrupeds, as well as 



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