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," (Apterodytes 

 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 be, 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 be 

 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, but 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 bruked and reduced. Many 

 experiments have been made to ascertain the precise manner 

 in which the gizzard acts; but 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 be both felt, seen, and heard. On pressing with 



* Edinburgh Philosophical Journal, No. III., p. 206. 



