Morality does not consist solely of duties towards human beings; it is more general: it extends to every being capable of suffering. The physiologist is not an ignoramus, neither is he a barbarian; and he has right well understood this duty. Physiologists have concluded that experimentation upon living animals is necessary, and it is the many reasons which have led them to this opinion which I propose to set forth. But it will, I hope, be quite understood that my defence of vivisection implies no contempt, no raillery, no unfriendly sentiment towards those who oppose it. My opponents are not always courteous or loyal in their polemics; but that is of no importance; and I shall reply only to such objections as are potent, able, and rational. In other words, I shall take from among the arguments of anti-vivisectionists those only which can be called legitimate, those which deserve to be studied methodically and profoundly by every man of good faith. I shall deliberately put on one side both abuse and nonsense. I should here mention an anonymous leaflet which has received a considerable amount of publicity in England ("How Scientific Cruelty is defended," London, 1907, 4 pp.). In this leaflet, a reply is given to an article which I once published on Vivisection. Certainly, after a lapse of twenty-six years, I might claim the right to abjure some of the notions of my youth. Taken as a whole, however, my ideas concerning vivisection have changed but little, and I still consider it to be necessary. I of course recognise that the number of physiological laboratories, which I estimated at thirty in my article, is for present-day purposes too low. During the last twenty-six years their number has very considerably increased. But a laboratory of physiology does not necessarily mean a laboratory of vivisection. There is the whole range of physiological chemistry, the study of ferments and psychological physiology, not one of which makes any demands on vivisection. Many eminent physiologists--for example, my former master, M. Marey--have performed very little vivisection. Even in those laboratories where vivisection is performed, it is not practised every day, and especially not upon dogs! Far from it! In Paris, for example, where every dog experimented upon is a stray animal handed over by the prefecture of police, there are only about six hundred dogs per annum thus available for experimentation. Now the laboratories in Paris represent, from the point of view of activity, at least half of all the laboratories in France put together. It is alleged that Schiff stated to Mrs Anna Kingsford that he had experimented on more than 14,000 dogs, that is to say, an average of one dog a day for fifty years! This is obviously an exaggeration, though it is difficult to trace now who was responsible for it.