If chloroform, for some reason or other, cannot be employed, many other anæsthetics, such as chloral and morphia, may be used. Chloral, in certain doses, produces complete anæsthesia, and it is easier to administer than chloroform. Formerly, chloral was injected, by a small puncture, into the veins of rabbits and dogs. I pointed out another method which allows one to avoid even the puncture; it is sufficient to make a rectal injection of the solution of chloral. In two or three minutes, the dog, the rabbit, or the guinea-pig, is seized with a kind of inebriety; he staggers, falls to the ground, and in about ten minutes he is completely anæsthetised. Large doses of morphia can be injected into animals without causing immediate death. An animal under a moderate dose of morphia does not absolutely lose all sensibility to pain; but the slight pain which he then feels is very transient. If the animal is submitted to strong excitation, he wakens for a few seconds, but soon falls back again into profound slumber. Morphia in moderate doses is not such a perfect anæsthetic as chloral or chloroform; it is therefore usual under such circumstances to administer also volatile anæsthetics like chloroform, and quite small quantities of the latter will then produce perfect anæsthesia. If, however, morphia is given in lethal doses, as is sometimes done for comparatively short experiments, it is an absolutely complete anæsthetic in itself, just as it is when a man takes a fatal dose of morphia, or of its parent substance, opium. Nevertheless, chloroform, chloral, and ether have a very serious disadvantage for the physiologist. They abolish sensibility, but, at the same time, they abolish the majority of the reflex actions in which voluntary muscles are concerned. Now, in many experiments, it is indispensable to be able to study such reflex movements, that is to say, the fundamental reactions of the nervous system. Thus, physiologists, more preoccupied, it must be said, with assuring the immobility than the insensibility of the animal, have had recourse to another substance, _curare_, the properties of which were investigated by Claude Bernard.