452 



A HISTORY OF 



be accounted for ; at least the knife of the 

 anatomist goes but a short way in the inves- 

 tigation. All we are certain of is, that birds 

 have much louder voices, in respect to their 

 bulk, than animals of any other kind ; for the 

 bellowing of an ox is not louder than the 

 scream of a peacock. 



In these particulars, birds pretty much re- 

 semble each other in their internal conforma- 

 tion ; but there are some varieties which we 

 should more attentively observe. All birds 

 have, properly speaking, but one stomach; 

 but this is very different in different kinds. 

 In all the rapacious kinds that live upon ani- 

 mal food, as well as in some of the fish-feeding 

 tribe, the stomach is peculiarly formed. The 

 oesophagus, or gullet, in them, is found replete 

 with glandulous bodies, which serve to dilate 

 and macerate the food, as it passes into the 

 stomach, which is always very large in pro- 

 portion to the size of the bird, and generally 

 wrapped round with fat, in order to increase 

 its warmth and powers of digestion. 

 < Granivorous birds, or such as live upon 

 fruits, corn, and other vegetables, have their 

 intestines differently formed from those of the 

 rapacious kind. Their gullet dilates just 

 above the breast-bone, and forms itself into a 

 pouch or bag, called the crop. This is re- 

 plete with salivary glands, which serve to 

 moisten and soften the grain and other food 

 which it contains. These glands are very 

 numerous, with longitudinal openings, which 

 emit a whitish and a viscous substance. After 

 the dry food of the bird has been macerated 

 for a convenient time, it then passes into the 

 belly, where, instead of a soft moist stomach, 

 as in the rapacious kinds, it is ground be- 

 tween two pair of muscles, commonly called 

 the gizzard, covered on the insidewith a stony 

 ridgy coat, and almost cartilaginous. These 

 coats rubbing against each other, are capable 

 of bruising and attenuating the hardest sub- 

 stances, their action being often compared to 

 that of the grinding teeth in man and other 

 animals. Thus the organs of digestion 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 sto- 



mach or gizzard. Birds are also careful to 

 pick up sand, gravel, and other hard substan- 

 ces, not to grind their food as has been sup- 

 posed, 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 are thus sup- 

 plied, 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 

 appendix 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 intestines is, in most birds, a 

 great way distant from the stomach; which 

 may arise from the danger there would be of 

 the bile regurgitating 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, because 

 they drink but little. They therefore have 

 no need of a bladder ; but their urine distils 

 down into the common canal, designed for re- 

 ceiving 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 abun- 

 dant, and is distinguished from the rest by its 

 white or silver colour. This part is found 

 not only in the whole intestinal canal, but is 

 seen also in the whole channel of the ureters, 

 which may be distinguished from the coats of 

 the kidneys by their whiteness. This milky 

 substance they have in greater plenty than 

 the more thin and serous part ; and it is of a 

 middle consistence, between limpid urine and 



