NATURAL HISTORY. 313 



Thy style's the same whatever be thy theme, 



As some digestions turn all meat to phlegm." DORSET. 



lighter, and of rising upon the air with greater ease : when they detcend, they 

 txhamt the cells^ and alight with greater ease. 



998. Why is the gizzard such, an important organ in the 

 structure of birds? 



Because it compensates for the absence of teeth, by triturating or 

 grinding the food, so as to render it fit for digestion. Every 

 particle of food which requires to undergo this operation, is sub- 

 mitted to the action of the two gristly surfaces which form a 

 portion of the organ, and produce a rotatory motion on 

 the food. 



999. In order to ascertain the peculiar powers of the gizzard, several experiments 

 have been resorted to, some of which would appear at first sight to be cruel, but 

 which in the end proved to be harmless. " Twelve strong tin needles," says 

 Spallanzani, " were firmly fixed in a ball of lead, the points projecting about a 

 quarter of an inch from the surface. Thus armed, it was covered with a case of 

 paper, and forced down the throat of a turkey. The bird retained it for a day and 

 a half without showing the least symptoms of uneasiness. Why the stomach 

 should have received no injury from so horrid an instrument I cannot explain : the 

 points of the twelve needles were broken off close to the surface of the ball, except 

 two or three, of which the stumps projected a little higher. Two of the points of 

 the needles were found among the food. The other ten I could not discover, either 

 in the stomach or the long track of the intestines ; and therefore concluded that 

 they had passed out." 



In another experiment, which, without knowing the previous facts, we might 

 justly have deemed still more cruel, Spallanzani tells us he fixed twelve small 

 lancets, very sharp both at the point and edges, in a similar ball of lead. " They were 

 such as I use for the dissection of small animals. The bail was given to a turkey 

 cock, and left eighteen hours in the stomach, at the expiration of which time that 

 organ was opened ; but nothing appeared except the naked ball, the twelve lancets 

 having been broken to pieces ; I discovered three in the large intestines, pointless 

 and mixed with the other contents ; the other nine were missing, and had probably 

 been voided. The stomach was as sound and entire as that which had received 

 the needles. 



" Two capons, of which one was subjected to the experiment with the needles and 

 the other with the lancets, sustained them equally well. My next wish was to know 

 how much time elapsed before the beginning of the fractures; and by repeated 

 experiments on turkeys I found that these sharp bodies begin to be broken, and lose 

 their shape, in two hours. This, at least, happened in two individuals of the species : 

 in one, four of the lancets, and in the other, three of the needles, were broken 

 within that apace ; the others were blunted, but continued fixed in the balls," 



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