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obtaining it pure, it is obferved to be of an afli or pale yel- 

 low colour, turbid, and of a tenacious confillencc, like mu- 

 cus. Spallanzani found it in feveral birds to have a bitter 

 and fait tallo, which he attributed to admixtrre with fomc 

 of the fluids contained in the inteftines ; he difcovcred alfo, 

 that the turbidity and the colour were produced by the exift- 

 cnce of a number of ycllov.- particles, too minute to be dif- 

 tinftly feen without the aid of the microfcope, and which 

 in a few hours fubfuhn^j to the bottom, left the fupernatant 

 liquor as tranfparent as water. He has remarked the yellow 

 tinge to vary in intcnl'ity, according to the Ipecies; in the 

 eagh, for iiulance, it is cineritious, and i:i the croiu a red- 

 dilh yellow colour, like the yolk of an egg. 



A number of the experiments perfi-i nied by Sparanzani, 

 although in f^me inllances he failed, (hew that the gallric 

 fluid of carvivorous b'trHs will ad upon vegct:ible matters 

 and upon the ut!i?rhand, that graminivorous birds can digell 

 animal food : hut his mofl interefting and ir.iportant experi- 

 ment on the properties of the gallric fluid, is that made to 

 determine its powers of refilling the operation of cold. " On 

 «a very cold day in winter," he fa\ s, " 1 cxpofed a fmall 

 "quantity (of tlie gallric juice of tiic eagle) in a glafs, on a 

 «' window, along with two other glafles containing water, in 

 •' one of whieh was diflijlvcd a quantity of common fait, fuf- 

 " licient to give it a Hronp:er tallc than the gallric fluid had. 

 " Thethermometers fet befule the glafTes Hood at five degrees 

 " below o (twenty ar.d thret-fourths, Faren. ). Of the three 

 " liquors, the fiill that was frozen, was the common water, 

 " the next was the fait water, and the lall was the gallric fluid. 

 " When I carried tirem into my apartment, where the tempe- 

 "rature was three and an half dcg. above o. the firlt that 

 "thawed was the gallric fluid, next the brine, and lallly the 

 " water." The conclufion which neccflarily refults from this 

 experiment is, that the gallric juice of birds, and from ana- 

 logy, that of other animals, is capable of refilling the ef- 

 feiEls of cold more than common fluids, or even thofe impreg- 

 nated with a great quantity of fait; and therefore it may be 

 confidered as poflcfUiig fome degree of vitality. If this fup- 

 pofition be admitted, it determines the nature of the digef- 

 tive procefs, fo long a quellion in phyfiology. 



The gallric fluid of the crow has been fubmitted to chemi- 

 cal examination by Scopoli, by which he difcovered that it 

 contained a quantity of gelatine and faponaceous fubft;ance, 

 fome muriate of ammonia, and phofphaLe of lime, with a 

 large proportion of water. 



The J'tcotul part of the organ of tl'ge/lion of I'lrJs, is not 

 lefs Angular than the llrufture jufl^ defcribed ; it immediately 

 iucceeds the zone of gallric glands, and when in the natural 

 fituation, occupies the left region of the abdominal cavity, in 

 which pofition it is retained by the feveral reflexions of peri- 

 toneum, which conllitute the air cells. From being the part 

 into which the food is received in order to undergo the pro- 

 cefs of digellion, it has commonly received the diftinftive 

 appellation offlomach : but it would feem more confillent, not 

 only with the form of the digellive organ in fome birds, and 

 with its fuiiftions in other animals, to apply the term ftomach, 

 both to the gallric glands, and to the mufcular bag which im- 

 mediately receives their fecretion, and the food ; or for the 

 greater convenience and clearnefs of defcription, the lower 

 portion of the llomacli might be dillinguifhed from the 

 bulbus glandulofus, by the name of ventricle. 



The greatcll variety exifls with refjxra to the (Irufture of 

 this part of the organ of digellion in birds : when it poflfeires 

 a certain degree of mufcubrity, it is well known under the 

 uzmeoixht gizzard ; and when its mufcles are fo thin as to 

 give it the appearance of a Ample bag, it is commonly, though 

 erroneoully, called a membrano-us llomach. 



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Tourcroy attempted to eflablifli two clafTes of birds, ac« 

 cording to the formation of their llomachs, calling the one 

 viyogaflrlques, and the otiier hymenogaflr'iques, but thefe 

 terms were only applicable to the two extremes. 



Vic d'Azir has admitted three dillinclions in the ftruflurc 

 of the ventricle ; the firll that of the true gizzard, of which 

 he gives iuftances in the gal/in.-e, thcfwan, the goofe, &c. ; the 

 fecoi.d where the mufcles which compofe the gizzard are 

 not dillinCl from the other parts, nor vciy ftrongly marked, 

 as in the thnijh and jay ; the third is the membranous llo- 

 mach, as it is called, which is found iu the heron, eagle, cor- 

 morant, &:c. See the introdudlion to Vic d'Azir's great 

 Syllem of Anatomy. 



Thefe dillinftions are not, however, juft ; the gradation 

 from the molt mufcular gizzard to the thinneil ventricle, is 

 regular and uninterrupted ; in order to underftand whieh, 

 and the other variations in llr jtture, it is neceffary that the 

 true g zzard, or mufcular llomach, be lirll defcribed. 



The external form of this organ is ufu:illy an irregular 

 oval, the two ends of which are made of the great lateral or 

 cligajlrie mufcle. 



Tiiis mulcle conftitutes the principal mafs of the gizzard ; 

 its attitude with refpedl to the buibus glandulofus is nblique. 

 The two flefhy portions are united by means of a ftrong flat 

 tendon, on each lide of the gizzard, which in the centre is 

 dillinCt from the parietes of the ventricle. 



Thepoition of the llomach, which appears between the two 

 flefliy mallcs of the digallric mufcle, and which is croflfed by 

 the tendon, belongs to the cavity of the ventricle ; it is com- 

 pofed of flelhy fibres, pafling in feveral direftions, as may be 

 moll convenient for diminilhing the cavity. Many of thefe 

 fibres are continued into the fubftance of the digallric mufcle, 

 and others run in its outer margin, thus giving integrity and 

 connexion to thefe two portions of the ventricle. See Plate 

 W.fig. r. in the Anatomy of Birds, which reprefents the ex- 

 ternal appearance of the llomach of the 'wild fzvan, bl, the 

 flefliy parts of the digallric mufcle, c, the tendon connefting 

 them to each other, d, the parietes of the ventricle on the 

 fuperior part, e, the fame, inferiorly, f the margins of the 

 digallric mulcle, with fibres pafling along them. 



The difpofition of the fibres in the interior of the digaftric 

 mufcle is exceedingly curious. They appear, upon a fuper- 

 fieial view, to be arranged in thin concentric laminx, fepa- 

 rated from each other by the moll delicate tendon. Thefe 

 layers pals to the lateral tendons on the circumference, fo 

 that their force is exerted upon them. See Plate III. fig. I. 

 which is the fcAion of the gizzard of the goofe, a a, the two 

 great maffes of the mufcidar fubftance, h,b, the tendons by 

 which they are connecled to each other. But if another 

 ledlion be made, parallel to the fides of the gizzard, or acrofs 

 the concentric layers, we have found each of thelaminje to 

 be divided by a great number of dehcate tendinous procefles 

 which form with each other fquares and triangles of various 

 fliapes, producing a reticulation, not unlike a honeycomb. 

 The extraordinary multiphcation of mufcular fafciculi, which 

 arifes from the lamellated and reticulated ilrutture of the 

 gizzard, creates a force which almoll furpafles calculation. 



On laying the gizzard open by cutting through the 

 tendon, which is the thinnell part, it is obferved to be co- 

 \ered internally with a rude, callous fubftance, of a dark 

 brown colour ; this is thin and pliable upon the portion of 

 the ventricle, not inclofed by the digallric mufcle, and par- 

 takes of the motions of the cavity ; but when it covers tiiat 

 mufcle, it becomes as tough and inflexible as the hoof of a 

 quadruped ; two oval furfaces are feen to projeft beyond the 

 other parts ; they are raifed upon the interior of the thickell 

 portions of the digaftric mufcle, and the horny integument 



wliea 



