Eiaus. 9 



each other, are capable of bruising and attenuating the hardosl 

 substances, their action being often compared to that of the grind- 

 ing teeth in man and other animals. Thus the organs of diges. 

 tion are in a manner reversed in birds. Beasts grind their food 

 with their teeth, and then it passes into the stomach, where it is 

 softened and digested. On the contrary, birds of this sort first 

 macerate and soften it in the crop, and then it is ground and 

 comminuted in the stomach or gizzard. Birds are also careful 

 to pick up sand, gravel, and other hard substances, not to grind 

 their food as has been supposed, but to prevent the too violent 

 action of the coats of the stomach against each other. 



Most birds have two appendices, or blind-guts, which, in 

 quadrupeds, are always found single. Among such birds as ai-e 

 thus supplied, all carnivorous fowl, and all birds of the sparrow 

 kind, have very small and short ones ; water-fowl and birds of 

 the poultry kind, the longest of all. There is still another ap- 

 pendix observable in the intestines of birds, resembling a little 

 worm, which is nothing more than the remainder of that passage 

 by which the yolk was conveyed into the guts of the young 

 chicken, while yet in the egg and under incubation. 



The outlet of that duct which conveys the bile into the in- 

 testines is, in most birds, a great way distant from the stomach ; 

 which may arise from the danger there would be of the bile re- 

 gurgitating into the stomach in their various rapid motions, as 

 we see in men at sea ; wherefore their biliary duct is so con- 

 trived, that this regurgitation cannot take place. 



All birds, though they want a bladder for urine, have large 

 kidneys and ureters, by which this secretion is made, and carried 

 away by one common canal. " Birds," says Harvey, " as well 

 as serpents, which have spongy lungs, make but little water, be- 

 cause they drink but little. They therefore have no need of a 

 bladder ; but their urine distils down into the common canal, de- 

 signed for receiving the other excrements of the body. The 

 urine of birds differs from that of other animals : for, as there 

 is usually in urine two parts, one more serous and liquid, the 

 other more thick and gross, which subsides to the bottom ; in 

 birds, the last part is most abundant, and is distinguished from 

 the rest by its white or silver colour. This part is found not 

 oidy in the whole intestinal canal, but is seen also in the whole 

 channel of the ureters, which may be distinguished from the caats 



