Frogs, etc., are perfect thermometers. Some that I had in a firkin were chilled to stiffness, while their fellows buried themselves again in the mud of the meadows; i. e., in a cold night at this season they are stiffened in a tub of water, the small R. palustris, not being able to bury themselves in mud. They appear to lose their limbs or portions of them, which slough off in consequence.