This skin is covered by a thick epidermis, which is periodically detached in its entirety, most frequently in a single piece. Before effecting its _moult_, the reptile remains in a state of complete repose for several weeks, as if asleep, and does not eat. Its scales grow darker and its skin becomes wrinkled. Then one day its epidermis tears at the angle of the lips. The animal thereupon wakes up, rubs itself among stones or branches, divests itself entirely of its covering as though it were emerging from a sheath, and proceeds forthwith in quest of food. The _moult_ is repeated in this way three or four times every year. CHAPTER II. _HABITS OF POISONOUS SNAKES. THEIR CAPTURE._ All poisonous snakes are _carnivorous_. They feed on small mammals (rats, mice), birds, batrachians, other reptiles or fish, which they kill by poisoning them by means of their fangs. They almost always wait until their prey is dead before swallowing it. Some of them are very fond of eggs, which they well know how to find in the nests of birds, and swallow whole. When a poisonous snake wishes to seize its prey, or strike an enemy, it raises its head, and depresses the lower and elevates the upper jaw in such a way that the _fangs_ are directed straight forward. Then, with the quickness of a spring when it is released, the reptile makes a sudden dart and strikes its victim. After inflicting the wound it draws back, doubles up its neck and head, and remains prepared to strike again. So rapid is the action of the venom, that the wounded animal falls to the ground almost immediately; it is forthwith stricken with paralysis, and dies in a few moments. In most cases the snake holds it in its mouth until death ensues; the reptile then sets to work to swallow its victim, an operation which is always slow and painful. In captivity poisonous snakes almost always refuse to take any food whatever. If it be desired to keep them for a long time, it is often necessary to resort to artificial feeding. For this purpose the snake is seized by the head by means of a strong pair of long forceps; it is then grasped by the neck with the left hand without squeezing too hard (fig. 15), taking care at the same time not to give the body a chance of coiling itself round anything. Next, one or more lumps of beef or horse-flesh are introduced into the jaws, and gently forced down deep into the œsophagus by means of a glass rod, which is polished in order not to injure the mucous membrane. The œsophagus is then gently massaged in a downward direction, in order to cause the bolus of food to descend into the stomach (fig. 16). This operation is repeated every fortnight. [Illustration: FIG. 15.--FEEDING A POISONOUS SNAKE, FIRST STAGE.] [Illustration: FIG. 16.--FEEDING A POISONOUS SNAKE, SECOND STAGE.] [Illustration: FIG. 17.--CATCHING A _Cobra-di-Capello_ (_Naja tripudians_), FIRST STAGE. (At the French Settlement of Pondicherry, in India.)]