XU 
INTRODUCTION. 
began to be obliterated and broken, in about two hours. Although the 
stomach of the Turkey appeared invulnerable to their action, yet two 
pullets suffered, as philosophical martyrs, under the torture of similar 
experiments. They were compelled to swallow headless pins ; one died 
in consequence in eight, and the other in thirty-two hours. To a pigeon 
he gave an unpolished garnet, which remained in its stomach nearly a 
month; and though this stone was so large as almost to fill the cavity of 
its gizzard, the animal fed well, nor was the interior coat lacerated. And 
he draws these general conclusions from the whole of his observations, 
notwithstanding the above facts recorded of the pullets, that the stomachs 
of birds of the gallinaceous kinds, are not usually obnoxious to injury, 
from the introduction, and trituration of sharp substances, and that the 
muscular powers of their stomachs are capable of comminuting hard 
bodies, as well without pebbles® as with them. He further remarks, 
that so hard is the internal coat, that lines the cavity of the gizzard of 
granivorous birds, that he drew lancets, needles, and bits of glass, often 
across it, with considerable force, without doing any perceptible injury. 
A cursory inspection shows us, that the stomachs of the granivorous 
kinds are thick, globous bodies, and formed of muscles of enormous 
strength, lined by a wrinkled coat of uncommon firmness of texture ; 
still in all species of birds the gastric fluid prevails, but in a greater 
degree, where there is a want of the vast, muscular power, of the giz- 
® It was the opinion of the Florentine academicians, that hard substances were more readily 
broken, when the bird had many pebbles in its stomach, than when it had but few ; but Spallanzani 
proves, that birds having no pebbles in their gizzards, abrade and break down hard and sharp 
bodies, without injury ; and that trituration depends upon the strength and action of the gastric 
muscles alone, and not upon these foreign substances. — Spallanzani, Dis. I. Vol. P. 27. 
Doctors Hunter and Fordyce are of a contrary opinion ; they maintain the proposition, 
that asserts the utility, and necessity, of these pebbles, in grinding the food of granivorous birds •, 
but high as their authority indubitably is, it weighs but little against the well-conducted and 
numerous experiments of Spallanzani on this subject, and the opinion of Spallanzani is strongly 
supported by the well-known fact, that insectivorous birds swallow pebbles. 
