REPTILES. 



merely the bones remaining, wliile the other parts were 

 nearly as perfeft as if they had been fwallovvcJ the fame 

 day. Spallaiizani confirmed this want of digeilive power 

 in the oefophagus, by direiit experiment; ^ 125. Natii- 

 raliils, fays this indefatigable inquirer, were already ;ip- 

 pri^ed of tiic tardinefs of digeftiuu in fcrpents. Bomare, 

 in his Dia. d'Hilt. Naturelle, gives an account of a fer- 

 pent at Martinique, which retained a chicken m its ilomach 

 for three months, and did not con.plctely digefl it. « It is 

 remarkable that flefli does not become fretid from rcmam- 

 ing long in the llomachs of thefe cold animals, which I 

 had occafion to obferve particularly in a viper. A lizard 

 was retained in its Ilomach for fixtecn days, at the end of 

 which time it had no odour but that of the gallric juice. Yet 

 fuch was the iieat of the feafon, that another lizard, which I 

 had placed in a clofe veffel, containing a little water, emit- 

 ted an infupportable llench before the expiration of the third 

 day ; j 127. The galtric liquor of a fnake approaches in 

 colour to that of foot ; it had the fluidity of water, and 

 evaporated very (lowly ; it had both a fait and bitter tafte, 

 and was not inflammable. It ftrongly refembled thegaftric 

 fluid of other animals, and this refemblance extended to the 

 odour, which was exadly like that of the correfponding 

 juices of birds of prey ; ^i 123. 



The idea of Blumenbach, tiiat the venom of the poifon- 

 ous ferpents fuppHes the place of maltication, and promotes 

 digeilion by fome feptic power, feems completely unfounded. 

 It is a provifion calculated merely for purpofes of off'ence. 

 Where is this feptic power, or wliat fupplics its place in 

 the harmlefs ferpents, and in all other amphibia ? 



The whole alimentary canal of the amphibia abounds 

 with a vifcid tenacious mucus, the abode of feveral genera 

 of worms. 



Blumenbach failed completely in very numerous and 

 di.verfified attempts to cram frogs and lizards with madder 

 root, and thus to produce in their bones that beautiful rofe 

 colour, which is fo quickly produced in the mammalia of 

 birds, when thus fed. Specimen Phyfiol. p. 31. 



Jbforbing Vejfels. -This fyllem has been very httle exa- 

 mined by anatomifts, probably on account of the minute- 

 nefs of the tubes, and the confequent difiiculty of injefting 

 them. We have nothing to add to the account given by 

 Hewfon, who firfl defcribed them in the Philofophical 

 Tranfadions, 1769. 



No lymphatic gland has been yet feen in a reptile : birds 

 ha-ve none in their mefentery, but they are feen connefted 

 to the large lymphatics of the neck. 



It has been afl'erted that the chyle is colonrlefs, and hence 

 anatomifts have explained why the vell'els were fo long un- 

 difcovered. In animals which have white chyle, the ap- 

 pearance of this fluid through the tranfparent coats of the 

 lafteals fupphes the place of injecfion, and affords an eafy 

 method of demonftrating them. Mr. Hewfon ftates that he 

 faw white chyle in a crocodile. 



The diftribution of the lafteals (if that term may be 

 employed where the chyle, inftead of being like milk, is 

 tranfparent) on the inteitine of the turtle, forms one of the 

 moll elegant preparations in comparative anatomy. By 

 fixing the injedting tube in a veffel near the inteftine, and 

 waiting with a little patience, the quickfilver will gradually 

 find its way into the minute ramifications of the lafleals. 

 The large trunks on the mefentery contain valves, fo that 

 we cannot fucceed in filling the abforbents of the inteftine 

 from them ; but the ramifications on the inteftine itfelf are 

 deftitute of thefe folds, fo that when once the quickfilver 

 has reached the furface of the gut, it will run forward with- 

 fcint ^\\\. obftacle. The peritoneal furface of the gut is com- 



pletely covered with ftraiglit parallel branches, running- 

 according to the length of the inteftine. Its inner furface 

 is no lefb thickly covered with lafteala of a d'ftereiit appear- 

 ance. When dried it feems as if the quickfilver were con- 

 taiiiL-d in fmall cells, covering tlie whole internal furface of 

 tlie inteftine fo completely, tliat the point of a pin could 

 fcarcely be placed between them. Mr. Hewfon ha* parti, 

 cularly defcribed this appearance, and was doubtful whether 

 it ought to be referred to extravafation or not. But we are 

 convinced, from frequent examniations of this cellular ftruc- 

 ture, that it is a part of the natural organization ; becaufe 

 the cells are reirular and uniform in their fize and arrange- 

 ment ; no force is ufed in the experiment ; and a real extra- 

 vafation prefents an appearance altogether different. The 

 extent of the abforbing fyftem, as demonftrated in this way, 

 is beyond any thing we could form an idea of from injedlions 

 in man or warm-blooded animals. 



After leaving the inteftine, the lafteals accompany the 

 blood-velfels on the mefentery, running at their fides, and 

 communicating acrofs them. Eacli artery has two veins, 

 and there is a lafteal or more at each fide of each of the 

 three veffels ; fo that their number confiderably exceeds that 

 of the blood-vefl'els. A coarfe reprefentation of them, on 

 the mefentery, is exhibited in Monro's Phyfiology of Fifhes, 

 tab. 30. 



Near the root of the mefentery the large lacfeals anaf- 

 tomofe, fo as to form a net-work, from which feveral large 

 branches go into fome confiderable lymphatics on the left 

 fide of the fpine. Thefe laft can be traced downwards 

 almofl to the anus, and belong to the parts fituated below the 

 mefentery, and particularly to the kidnies. At the root of 

 the mefentery, on the left fide of the fpine, the lymphatics 

 of the fpleen join the lafteals, and immediately above this 

 union a fort of plexus or net-work is formed, which lies 

 upon the right aorta. Flom this plexus a large branch arifes, 

 which pafles behind the right aorta to the left fide, and 

 gets before the left aorta, where it aflifts in forming a large 

 receptaculum, lying in front of that artery. The thoracic 

 dufts arife from this receptaculum. From its right fide goes 

 one trunk, which is joined by that large branch which came 

 from the plexus to the left fide of the right aorta, and then 

 paffes over the fpine. This trunk is the thoracic duft of 

 the right fide ; for having got to the right fide of the fpine, 

 it runs upwards on the infide of the right aorta, towards the 

 right fubclavian vein. And when it has advanced a little 

 above the lungs, or within three or four inches of the fubcla- 

 vian vein, it divides into branches, which, near the fame place, 

 are joined by a large branch that comes up on the outfide of 

 the aorta. From this part upwards, thofe veffels divide and 

 fubdivide, and are afterwards joined by the lymphatics 

 of the neck, which likewife divide into branches before 

 they join thofe from below ; fo that between the thoracic 

 duft and the lymphatics of the fame fide of the neck a very 

 intricate net-work is formed. From this net-work a branch 

 goes into the angle made by the jugular vein, and the lower 

 part, or trunk, of the fubclavian : this branch, therefore, 

 lies on the infide of the jugular, whiltt another gets to the 

 outfide of that vein, and feems to open into it a httle above 

 the angle between that vein and the fubclavian. Into the 

 above-mentioned receptaculum the lymphatics of the ftomach 

 and duodenum enter : tliey have numerous analtomofes, 

 forming a beautiful net-work round the artery which they 

 accompany. From this receptaculum hkewife, befides the 

 trunk already mentioned, which goes to the right fide, 

 arife two other trunks, nearly equal in fize ; one of which 

 runs upon the left fide, and the other upon the right fide of 

 the left aorta, till they come within two or three niches of the 



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