246 ANOURA. RANAD^. 



mention without reprobation) after tlie lungs 

 had been totally cut out. It is necessary, how- 

 ever, that the skin should be maintained con- 

 tinually moist ; for if it become dry, its action 

 ceases, and death is the speedy result. " But," 

 remarks Professor Bell," as the frog is frequently 

 exposed to a dry atmosphere, it is essential that 

 there should be some provision made for a 

 constant supply of moisture to the skin. This 

 is effected by a secretion of fluid from the sur- 

 face itself. The extent of the skin is, however, 

 so great that the whole internal moisture of the 

 animal would speedily be exhausted, unless a 

 reservoir were provided for an extraordinary 

 demand ; and I now proceed to shew what this 

 reservoir is, and by what means it is replenished. 

 Every one knows that when a Frog is hastily 

 seized, or even quickly pursued, it voids a con- 

 siderable quantity of water, which is generally 

 but erroneously, supposed to be the urine. This 

 water is limpid and pure, containing no traces of 

 the usual component elements of the urinary secre- 

 tion. It is contained in a sac, which has also been 

 mistakenly believed to be the urinary bladder. 

 This is the reservoir to which I have alluded. 

 A^Hien, therefore, the frog is happily placed in a 

 damp atmosphere, or in the water, the skin absorbs 

 a quantity of water, which there is every reason to 

 believe is secreted into the bladder just mention- 

 ed, where it is kept in store until the dr}mess of 

 the skin requires a supply for the purpose of respi- 

 ration, when it is again taken up, and restored to 

 the surface, by which it had been first absorbed."* 

 The Frog is capable of being tamed, and of 



* " British Reptiles," 79. 



