mention without reprobation) after the lungs had been totally cut out. It is necessary, however, that the skin should be maintained continually 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 surface 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 considerable 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 secretion. 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. When, 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 mentioned, where it is kept in store until the dryness of the skin requires a supply for the purpose of respiration, when it is again taken up, and restored to the surface, by which it had been first absorbed.”[1]
The Frog is capable of being tamed, and of
- ↑ “British Reptiles,” 79.
