We must, however, give to the word "Vivisection" its largest acceptation. It is not only a question of cutting nerves, of stimulating the glands, or of exciting the muscles. There are experiments of much longer duration in which there is no mutilation properly speaking, but _intoxication_,[7] produced by the injection of poisons and disease germs. It is, indeed, evident that pain can be provoked in other ways than by a sharp-edged instrument, which can always be done under anæsthesia. But may inoculation be performed? May prolonged _intoxication_ be caused? To treat the question in all its fulness, we will put the problem in the following manner. In order to study a disease, have we the right to give that disease to an animal? For my part, there can be no doubt on the point, and I affirm that such is our right. As a matter of fact, and as every unbiassed person is forced to recognise, it is only by experimentation that these diseases can be studied thoroughly. Clinical observation, bearing exclusively upon man, can only give incomplete results, much poorer, though its documents are multitudinous, than the results furnished by experimentation, which can be infinitely varied at will. If we were limited to the Hippocratic method of observation, which consists in studying the symptoms and the progress of a morbid affliction, we should be reduced to poor enough resources; and if meditation on the aphorisms of Hippocrates constituted the whole extent of our medical science, medical science would be a sad vacuum. Fortunately, however, such is not the case. Marvellous progress has been realised, which allows us to entertain quite other ideas than those of the Father of Medicine on the nature of diseases, and consequently on their treatment and their prevention. Those very persons who rise up in arms against physiological experimentation would not, I imagine, desire to be handed over to the care of a Hippocratic doctor if they were ill, to a doctor who took no notice of any modern discoveries under the pretext that they were acquired by experimentation _in anima vili_. If, however, we wish to discuss the problem thoroughly, it will not do to remain on indefinite ground. Let us arrive at precise facts. I will mention only three discoveries, the importance of which is considerable, and which have been established solely by experimentation.