124 FACULTIES OF BIRDS. 



angular substances which maybe swallowed*; but 

 Spallarizani has shown by his experiments that the 

 muscular action of the gizzard is equally powerful, 

 whether the small stones are present or absent. To 

 ascertain this point, he took wood-pigeons the moment 

 they escaped from the egg, and fed and nursed them 

 himself till they were able to peck. " They were then,'* 

 he continues, " confined in a cage and supplied at first 

 with vetches soaked in warm water, and afterwards in 

 a dry and hard state. In a month after they had 

 begun to peck, hard bodies, such as tin tubes, glass 

 globules, and fragments of broken glass, were intro- 

 duced with the food. Care was taken that each pigeon 

 should swallow only one of these substances. In two 

 days afterwards they were killed. Not one of the 

 stomachs contained a single pebble ; and yet the 

 tubes were bruised and flattened, and the spherules 

 and bits of glass blunted and broken. This happened 

 alike to each body, nor did the smallest laceration 

 appear on the coats of the stomach. 



44 I did not confine my observations to this one 

 species. With the same view, I set under a turkey- 

 hen several eggs, partly her own, and partly of a 

 common hen. When the chickens were hatched I 

 took charge of them myself, and employed the same 

 precautions as with the wood-pigeons. They were 

 confined for fifty-five days in separate cages, and 

 their food consisted of various sorts of grain. The 

 last days they had, to live I introduced into their 

 gizzards hard indigestible substances. Upon exami- 

 nation the stomachs appeared to be free from stones, 

 yet the fragments arid spherules of glass, and the tin 

 tubes, were not on this account either the less or the 

 more bruised or broken. Hence then,' 5 he adds, " we 

 have at length a decision of the famous question 



* See Smellie, Philosophy of Natural History, vol. i. ch. 8. 



