. The biology of the frog. Frogs. HABITS AND NATURAL HISTORY OF THE FROG 63 first molt, which occurs from* late in February to early in April, a second molt follows in the latter part of May or the first part of June, a third in July, and usually a fourth in August. In colder seasons the period of the molt comes later, and the fourth molt may then not occur. Five molts were not observed even during the warmest summers. Frogs often eat their shed skin after they have rubbed it off with the aid of their feet. The same habit has been observed in toads and in the large salamander, Cryp- tobranchus
. The biology of the frog. Frogs. HABITS AND NATURAL HISTORY OF THE FROG 63 first molt, which occurs from* late in February to early in April, a second molt follows in the latter part of May or the first part of June, a third in July, and usually a fourth in August. In colder seasons the period of the molt comes later, and the fourth molt may then not occur. Five molts were not observed even during the warmest summers. Frogs often eat their shed skin after they have rubbed it off with the aid of their feet. The same habit has been observed in toads and in the large salamander, Cryp- tobranchus. Hypnotism.—A frog may be thrown into the so-called hypnotic state in several ways. If it is seized in the hands, laid upon its back, and held a few moments until it has ceased its struggles, it will usually remain motionless for a consid- erable time, sometimes for hours. The position taken is a variable one. There is a tendency to assume an attitude such as would be produced if the movements of the frog were checked sometime during its efforts to regain an upright position. According to Verworn,1 the muscles in- volved in the righting movements are in a state of tonic con- traction as if these movements were suddenly inhibited. The breathing movements and the heart beats are at first accel- 1 Verworn, "Die sogenannte Hypnose der Thiere," Fig. 15.—Rana temporaria in the so- called hypnotic state. The upper figure shows the position assumed when the back is rubbed with the finger. The same attitude is main- tained when the frog is placed on its back, as is shown in the lower figure. (Modified from Verworn.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Holmes, Samuel J. (Samuel Jackson), 1868-. New York : The Macmillan company
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Keywords: ., bookauthorholmessamueljsamuelja, bookcentury1900, bookdecade1920
