INTRODUCTION. 
IX 
gullet. After the food has undergone this operation, it does not descend, in 
most of the species, immediately into the true stomach, or gizzard, but first 
into the lower extremity of the gullet, where that tube dilates, and there 
it remains for some time, under the action of the liquor secreted from its 
surface." This expansion of the oesophagus is called by some the ventriculus 
succenturiatus, or bulbus glandulosus, and by others the echinus, from the 
tubercular appearance of its interior, and supposed resemblance to the Sea 
Urchin. The gizzard, in most birds, is situated just under the lower part of 
the sternum, or breast bone ; but in the Cuckoo, Land Rail, Goatsucker, 
Rook, Jay, Great Titmouse, Kingfisher, and a few others, it rests upon 
the abdominal viscera, behind the sternum, and forms a protuberance in 
the belly. It consists of four most powerful muscles, composed of strong 
compact fibres, covered externally with a tendinous coat, and lined with 
numerous nervous filaments, which are guarded internally by a very tough, 
ridgy, yellow membrane, of uncommon strength, and almost cartilaginous. 
They are readily distinguished from the other muscles by their color, and 
by their amazing firmness of texture. Their action is so prodigious, that 
they leave marks of their effects on the hardest metallic bodies, and reduce 
to po wder solid globules of glass ; and such is their pow er that the grain 
devoured by the bird is as completely triturated, and rendered fit for the 
operation of the gastric juices, as if it had passed between the rollers of a 
mill. The small, rough pebbles, taken into the gizzard by birds, though 
commonly supposed to assist digestion, are not at all necessary in the 
business of trituration, as demonstrated by Spallanzani. He proves, by the 
most convincing experiments, that the gizzard is as capable of reducing 
grain into a pultaceous mass without, as well as with them. They have 
which had absorbed an ounce of It in so short a period. From a Turkey he obtained seven 
ounces in ten hours. — Spallanzani I. Vol. Dis. 
^ In dissecting Shags, Guillemots, Ra^or Bills, and other water fowl, I have found parts of 
fish of different kinds, but particularly the Sandeel, (ammodyt?s tobianus) or Sprat, as it Is 
commonly called in Devonshire, lodged in the oesophagus, and . partially digested, most probably 
by the action of this fluid. 
Q 
