Snakes in menageries have been known to manifest inactivity and disinclination for food as early as September if the season be unusually cold, at other times in October; but, on the contrary, during a milder season they keep active until November, while some do not hibernate at all. Their habits there can, however, scarcely be cited as normal, since the artificial heat regularly maintained in the Ophidarium never permits the rigours of an out-door winter to affect them. Nevertheless they manifest the disposition for repose; and if it could be so arranged that the tropical snakes could be submitted to tropical heat and drought, and those of cooler countries to frosty air, as in a state of nature, we might witness both estivation and hibernation under the same roof. A partial hibernation is observable in reptiles in captivity when, though not absolutely inactive, they decline food. For twenty-two weeks a python at the Zoological Gardens fasted during one winter; at another time, twenty weeks. The large python (_reticulatus_) fasted for one year and eleven months, covering two winters, but fed well and retained its health after this. Meanwhile, during this prolonged fast, should a gleam of sunshine penetrate the foggy atmosphere of our London winters, and shine through the glass roof upon a constrictor’s coverlet, he may slowly emerge therefrom, displaying a few feet of his lazy length for an hour or so, thus verifying the words, ‘obedient to the external atmosphere.’ No creatures are so susceptible of the changes of temperature; and the same degree which caused them to seek a retreat will, on the return of spring, reanimate them. And warmth—in them almost another word for vitality—equally affects their appetite. In the very height of summer, should their feeding-day prove a chilly one, a much lighter drain on the larder is observable, while a warm, bright day will show a heavy poulterer’s bill _in re Ophidarium_. Dr. A. Stradling, a practical ophiologist, found that the common English snakes ‘thrive exceedingly by reason of their increased appetites,’ when taken to the tropics. ‘It is impossible to say what degree of heat a reptile will not stand and enjoy,’ says this writer (_Field_, July 28, 1881). ‘On the hottest days in the hottest places on earth, one surprises snakes and lizards basking in the blazing sun-glare, on sands and rocks which it would almost blister the hand to touch.’ Florida is the most southern extreme of my own experience; but during a summer there one could not rest the hand on the almost burning stones and walls on which the reptiles delightedly reposed; and even in England, during a hot August, my little Bournemouth lizards were positively hot to the touch when basking in the full power of a bright noon sun. Dumeril corroborates these facts when he says some reptiles can endure a temperature higher than blood-heat. Sometimes in early spring he found a snake seeming to be asleep under a very hot wall which had been