60 THE STOMACH. 



in very small quantities, in proportion to the pro- 

 gress 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 experi- 

 ments 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 

 the finger, the muscles will feel to the touch as hard as 

 stones; when they relax, the grain, upon which they 

 were then working, passes on, and a further supply, 

 as in the case of the mill, passes under these natural 

 rollers. These alternate actions succeed each other 

 slowly but regularly ; and on placing the bird close 

 to the ear, as the food and stones roll under the 

 pressure of the muscles of the gizzard, a sound not 

 unlike the noise of the tide rolling upon a shingly 

 shore, may be distinctly heard at intervals, as if the 

 waves were ebbing and flowing ; and during all this 

 process, the gastric juice slowly flows in from the 

 lower part of the gullet or second stomach, and 

 mingles intimately with the digesting food. 



"We have stated that the fowl best calculated for 

 this examination should be a full-grown young one ; 

 but although, in this almost immature state, the 

 gizzard is fully developed, if we were to dissect a 

 chick, we should find not a vestige of a gizzard, but 

 merely a thin pellicle or skin. And it is for this 

 reason, that whereas the young fowl is nevertheless 



