ORDER CHELONIA. 85 



drupeds or serpents. The skin is naked in frogs and sala- 

 manders, scaly in lizards and serpents, covered with an 

 osseous shell in tortoises. Those which have a naked skin, 

 like all the batracians, are susceptible of absorbing a deal of 

 water through its pores, which to these animals is a substi- 

 tute for drink ; for though frogs and salamanders are often 

 plunged in water, they drink none of it ; but their skin 

 imbibes this liquid, and distributes it to the internal organs. 

 It even appears, from recent observations, that water partly 

 ministers to the respiration of these batracians, through the 

 skin : for we know that the skin in all animals has the power 

 of absorbing oxygen, and can thus receive this elemental gas 

 contained in the water, in the same manner as do the gills of 

 fishes. The water even collects in a sort of bladder, which it 

 has been supposed was intended to receive the urine ; but this 

 last secretion is immediately transmitted to the cloaca, or 

 intestinem rectum, by the ureters ; and the water of the blad- 

 der in toads and frogs, which has been regarded as a vene- 

 mous urine, has no more odour nor sapidity than distilled 

 water. 



Frogs and salamanders have certain glands upon the skin, 

 from which exudes an acrid and virulent humour, which in 

 the brown toad has the smell of garlick. A very dangerous 

 humour, of a similar kind, exudes from the feet of geckos. 

 The crocodile has, towards the neck, the anus, and under the 

 axilla, certain glands which spread a musky odour ; and 

 many tortoises exhale the like. Something analogous is found 

 about the glands of the thighs in lizards and chalcides, and 

 near the anus of amphisbenae, especially in the season of re- 

 production. Adders and serpents exhale a nauseous vapour, 

 which produces sensations of faintness, or even a putrid and 

 pestiferous odour, which the negroes can perceive at a very 

 considerable distance. Their prey does not seem to digest, 

 1)ut by putrifying in the stomach, which produces this disa- 



D 2 



