50 
THE STOMACH. 
ordinary contents of a common fowl’s stomach, in which were 
found three pieces of flint, three metal buttons, fourteen nails, 
several of which were very sharp, in addition to a great 
number of small stones.^ The coat of the bird’s stomach, 
with the exception of some slight scratches on the inner 
membrane, was in its natural state; probably, however, if the 
gizzard had been closely examined, it would have been found 
diseased or defective in its operations, thus inducing the 
fowl to make up its deficiency by so unnatural an addition. 
Sir James Ross, in his interesting voyage of discovery 
towards the South Pole, mentions having found in the 
stomach of one of the “ Great Penguin,” (Ajpterodytes 
Forsteri,) the frequenters of high southern latitudes, from 
two to ten pounds weight of pebbles, consisting of granite, 
quartz, and trappean rocks, swallowed/ no doubt, to assist 
them in digesting the various species of crustaceous animals 
on which they feed. 
But the best way of understanding its curious mode of 
working, will he, to follow the progress of a meal swallowed 
by a fowl, between whose stomach and that of a corn-mill, 
naturalists have traced a very close resemblance. The grain 
is first passed by the gullet into the craw, which may he 
compared to the hopper of the mill, through which the grain 
is gradually emptied on the grinding-stones. There, as we 
have seen, it remains a certain time, till it is considerably 
softened; and then, — not all at once, hut in very small 
quantities, in proportion to the progress of trituration, just 
as the hopper allows the grain to dribble into the central 
hole in the upper mill-stone, — does it pass onwards to the 
gizzard, where it is thoroughly bruised and reduced. Many 
experiments have been made to ascertain the precise manner 
in which the gizzard acts; hut we are still -much in the dark 
respecting it. We may learn, however, a good deal by 
examining a very lean young fowl, when, on removing the 
feathers from the side of the belly nearest the gizzard, its 
motion can he both felt, seen, and heard. On pressing with 
* Edinburgh Philosophical Journal , No. III., p. 206 . 
