ORGANIZATIONOFREPTILES. 19 



vomit a Tadpole, much altered, though not entirely changed in appearance, ten 

 days after it had been swallowed; and other Serpents have been observed to retain 

 tlieir food in this organ, for a much longer period, without completely digesting it. 

 Their slow digestion approximates this class to the inferior animals, as to the 

 Leech, in the stomach of which blood has been found many weeks after it had 

 been swallowed. Most Reptiles are voracious in the early summer months, yet 

 they never destroy more than is necessary for their sustenance, and all have great 

 power of abstinence, far beyond the higher classes, Spallanzani confined Toads 

 m close jars for more than twelve months, at the expiration of which time they 

 were lively and active. We have kept a Trionyx more than a year without food, 

 and Frogs and Serpents eight or nine months. 



3. Of the Absorbents. — These vessels are intimately connected with nutrition, 

 their office being twofold; the removal of such materials of the body as have 

 become useless, and the taking up of the nutritious part of the food from the small 

 intestines. Absorbents are found in most parts of the body, having thin transparent 

 parietes, and communicating frequently with the veins.* Those arising from the 

 small intestine are named lacteals: they absorb the chyle, and convey it to the 

 venous system; they are not easily recognised, but may be made conspicuous by 

 being injected with mercury. Valves exist in these vessels, but are not so thick 

 and firm as in the MaiBmalia.t In Serpents these vessels are extremely active; 

 they remove every particle of the almient taken into the stomach that is fitted for 

 nutrition, the entire foecal matter alone being expelled; and as there is no masti- 

 cation to disturb the relative position of parts, the hairs, and other indigestible 

 substances, are expelled together in a round mass.J In the Batrachian animals 

 the absorbent vessels are remarkably developed, having ventricles or pulsating 



* Lippi, of Florence, traced them to the vena cava, and Fohmann has demonstrated their 

 communication with many other veins. Anat. Untersuch. Heidelberg, 1S21. 

 tHewson, Phil. Trans, for 1769, p. 17S. 

 ± Dumeril, Hist. Nat. des Rept., tom. i. p. 145. 



