If that fails, I cannot advise you what to do, as I know nothing about the working of a watch.” Even though we open the living human body, as must be done for the purpose of making good such defects as are amenable to surgical treatment, and for a little while observe its wheels go round, we are unable, from fear of damaging the wheels, to introduce the mechanical tests which would tell us how and why they revolve. The man must be allowed to recover with uninjured organs. But, thanks to anæsthetics, there is no test which may not be applied to a live animal with as much propriety as to a dead one. Anæsthetics abolish the distinction, in its ethical applications, between life and death, because we are under no obligation, as in the case of the human being, to allow an animal to recover. Many experiments upon animals will be recorded in this book, and since the book is intended for the general public, who have been singularly misled regarding the nature and methods of vivisection, an opportunity is taken thus early of insisting that anæsthetics have made all things, not only possible, but legitimate. It is unnecessary to commence the description of each experiment with the statement that the animal was first placed in a condition of complete anæsthesia, or to end it with the statement that it was destroyed before it had recovered from the effects of the anæsthetic. The reader may take these facts for granted. In discussing the propriety of operating upon a living but unconscious animal, we are playing a word game as old as Plato’s day. What is life? What is the relation of the personality to the animal machine which it occupies and operates? For a few minutes a heart removed from the body continues to beat. In a physiological sense it is alive, although the body from which it was removed is dead. Yet the personality does not reside in the heart, as many generations of philosophers believed. It is merely an accident that the body dies when the co-ordinating mechanism, the heart, ceases to pump blood through its vessels. Nor is the personality limited to the brain. Without the sense-organs which place the brain in relation with the body, and owing to the movements of the body—by which the sources of sensations of smell, sight, hearing are ascertained—with the world of which it forms a part, there would be no personality, no Ego. Is it, then, coextensive with the body which exhibits it? A soldier returning crippled from the wars does not finish out his days with his personality curtailed. We are no nearer than was Plato to a definition of life. Such a discussion soon takes us out of the realm of science. Science is limited to the sphere in which the whole is greater than the part. Take away consciousness, and personality ceases. Guarantee that consciousness shall never return. The animal is dead. When considering the propriety of vivisection we must regard life and consciousness as inseparable. There can be no question of right or wrong in regard