DIETETICS. 



these quadrupeds have no triturating 

 power, and the aliment requires tritura- 

 tion, it ascends, in consequence of a gen- 

 tle stimulus to vomit, into the cavity of 

 the mouth, where, by means of rumina- 

 tion, it is put into the same state, previous 

 to being digested by the gastric fluid, as 

 happens to the food in. the stomachs of 

 granivorous fowls, after they have been 

 properly triturated by the gastric mus- 

 cles. 



Animals with intermediate stomachs, 

 such as ravens, crows, herons, &c. have 

 muscular stomachs, which are by no 

 means equal in force to the stomachs of 

 the first class, but much more so than 

 those of the third class. These animals 

 possess the privilege of returning sub- 

 stances they are incapable of digesting, 

 at least every nine, and in general every 

 two or three hours ; they are omnivorous. 

 Their gastric juice does not dissolve 

 whole seeds, they therefore bruise them 

 with their beak and feet, and they are 

 dissolved in twenty -four hours ; it soon 

 dissolves flesh and cartilage, but not bone. 

 The fluid in the oesophagus, Spallanzani 

 found inconsiderable as a menstruum, 

 when compared with that of the stomach, 

 since the first was six hours in dissolving 

 two parts of flesh, and the second one 

 hour only in dissolving six parts ; conse- 

 quently, the cesophagal liquor in the 

 craws of the gallinaceous is different 

 from that in this class. The resemblan- 

 ces between the gastric fluids of these 

 two classes may be reduced to five : 1st, 

 These fluids, besides being alike in co- 

 lour, are always salt and bitter, which 

 bitterness proceeds from the bile regurgi- 

 tating through the pylorus into the sto- 

 mach. 2dly, They are the immediate 

 agents of digestion, both in the muscular 

 and intermediate stomachs.independently 

 of trituration. 3dly, The fluids act in the 

 stomachs of these two classes of birds in 

 the same manner, in the solution of the 

 food ; they first soften, and next convert 

 the surface into a jelly, then produce the 

 same effect on the intermediate parts, 

 insinuating themselves gradually into its 

 substance until it is completely dissolved. 

 4thly, They do not entirely lose their 

 solvent power as soon as taken out of the 

 Stomach, provided they be heated to a 

 proper degree. 5thly,The origins whence 

 these fluids spring are nearly the same, 

 viz. the follicular glands with which their 

 organs abound. With respect to the dif- 

 ferences, they are in part reducible to the 

 inferior efficacy of the gastric fluid in 

 muscular, to that of the same fluid in in- 

 termediate stomachs* The gastric juice 



of the first is incapable of dissolving the 

 same aliment that the latter readily dis- 

 solves ; likewise, the food, wliich each 

 kind of gastric juice decomposes and di- 

 gests, is sooner subject to this change 

 from that which belongs to intermediate 

 stomachs : hence, artificial digestion suc- 

 ceeds much sooner with the first than the 

 second. The same inefficacy that the 

 gastric juices of birds with muscular sto- 

 machs shews in the solution of aliments 

 of a firm texture, extends also to their 

 cesophagal juices in the solution of soft 

 substances, notwithstanding the latter 

 are tolerably well decomposed by the 

 cesophagal juice of birds with interme- 

 diate stomachs. Another very striking 

 difference is, the prodigious force of 

 trituration in muscular stomachs, and the 

 weakness of the other, which greatness 

 of strength was necessary in birds whose 

 food is of considerable firmness, as seeds. 



Animals with membranous stomachs, 

 such as frogs, newts, snakes, fishes, rumi- 

 nating animals ; carnivorous birds and 

 beasts, as the eagle, falcon, man, dog, cat, 

 &c. this class is infinitelyjmore numerous 

 than the two former: it comprehends 

 nearly all the quadrupeds, fishes, reptiles, 

 birds of prey, and the greater part of in- 

 sects. 



From Spallanzani's experiments it ap- 

 pears, that carnivorous birds do not dis- 

 solve vegetables, and throw up the indi- 

 gestible part every twenty-four hours ; 

 that nature in these animals, whose diges- 

 tion depends on the gastric juice alone, 

 without any previous mastication or tri- 

 turation, has provided them with a much 

 larger quantity of it than the otherclasses; 

 that digestion is in proportion to the 

 quantity of this fluid ; that the gastric 

 juice of the ruminating class has no effect 

 in dissolving plants, unless they have been 

 previously macerated, and ground by the 

 teeth ; that its colour in sheep is green, 

 and yellow in cows ; that owls digest 

 flesh and bones, but not grain ; that their 

 gastric juice evaporates sooner than wa- 

 ter; that that of the eagle dissolves 

 bread and bone ; its colour is cineritious, 

 and it digests animal and vegetable mat- 

 ters out of the body ; that a wood-pigeon 

 may be brought by degrees to live on 

 flesh ; that the owl and falcon do not di- 

 gest bread; that the gastric juice of the 

 dog dissolves the enamel of the teeth ; 

 and that trituration is necessary in the 

 ruminating order and man, which is 

 produced by the teeth, as in gallinaceous 

 fowls by the gizzard ; but in other ani- 

 mals, as in the frog, newt, serpents, and 

 birds of prey, trituration does not contri- 



