FOOD OF POULTRY. 151 



speedily than a capon, while a goose performs the same oper- 

 ation sooner than either. Other experiments have proved that 

 needles, and even lancets, given to a turkey, were broken in 

 pieces and voided, without the stomach appearing to sustain 

 any injury from them. The reason undoubtedly is, that the 

 larger species of birds have thicker and more powerful organs 

 of digestion. 



The opinion has been almost universally received, that from, 

 some deficiency in the digestive apparatus, fowls have been 

 obliged to resort to the use of stones and gravel, in order to 

 enable them to dispose of the food which they consume. Some 

 writers have supposed that the use of these stones was to 

 sheathe the gizzard, in order to fit it to break into smaller 

 fragments the hard, angular substances which might be swal- 

 lowed. Spallanzani, however, has ascertained that this sup- 

 position is unfounded, by a series of experiments made with 

 this object in view. He took wood-pigeons as soon as escaped 

 from the egg, and nursed them under his own eye, until 

 they were able to peck. They were forthwith confined, and 

 in a month hard substances, such as tin and fragments of glass, 

 were introduced with their food, iln two days, they were 

 killed. No pebbles had been allowed to enter either one of the 

 stomachs, and yet these hard substances were bruised and flat- 

 tened, and the glass especially blunted and broken. Nor did 

 any wound or laceration appear on the coats of the stomach. 

 Similar experiments were tried, likewise, on the chickens of 

 the hen and turkey, with great care, and with effects precisely 

 similar. 



By some, the stones and gravel eaten by fowls have been 

 considered to have a medicinal effect ; and others have imag- 

 ined that they acted as absorbents for undue quantities of acids 

 in the stomach, while another office, namely, that of stimulants 

 to digestion, has been assigned to them. Extravagance has 



