Page:Popular Science Monthly Volume 77.djvu/362

356

N this most important and interesting phenomenon of nature—a truly protective phase—let us first briefly consider the natural-history side of the subject, describing how hibernation is peculiar to, and differs, in the various animals possessing this function of protective winter sleep. Then we will consider the various physiological phenomena characteristic of this torpid state. Let us first make clear the meaning of some of the terms used in connection with this condition.

The term "hibernation" is used by scientists and naturalists to signify the peculiar somnolent or torpid state in which many animals, both warm-and cold-blooded, inhabiting cold and temperate climes, pass the winter. On the other hand, in hot and dry countries, various animals pass into a similar condition during the hottest and dryest season of the year, and this state is called "æstivation."

Many of the animals which hibernate during the winter are liable to fall into a similar state at intervals during milder seasons—Dr. Marshall Hall considers the day sleep of bats as a species of hibernation and has called it "diurnation."

In man it is a question if true hibernation ever occurs—a similar condition may exist, however, but it is very rare either for a prolonged or short period. Cases of hibernation (?) in man are most frequently found in India, where some religious ascetics are stated, upon unimpeachable authority to possess the power of throwing themselves into a state closely resembling hibernation (trance?) for an indefinite period. Many curious cases have been recorded by Mr. Braid in his treatise on "Human Hibernation"; the most celebrated and best known is that of a "fakir," who, in the presence of Sir Claude Wade, the English governor, was buried alive at Lahore in 1837, was exhumed and restored to consciousness after remaining in the ground for several months, the grave being guarded and every precaution taken, in the meantime, to prevent any interference or disturbance of the body.

One of the largest groups of hibernating animals we have is that of bats—Dr. Marshall Hall claims that the bat when hibernating, practically never wakes, but when disturbed will breathe naturally, for a few minutes, but will then return to its former state of quiescence.