the modern scientist sees, very superficially in comparing the two. I have no doubt that Huxley was right in his inference "that if the properties of matter result from the nature and disposition of its component molecules, then there is no intelligible ground for refusing to say that the properties of protoplasm result from the nature and disposition of its molecules." It is undoubtedly in that nature and disposition of the biological molecules that Tyndall's whole "mystery and miracle of vitality" is wrapped up. If we could only grasp what it is that transforms the molecule of dead matter into the living molecule! Pasteur called it "dissymmetric force," which is only a new name for the mystery. He believed there was an "irrefragable physical barrier between organic and inorganic nature"--that the molecules of an organism differed from those of a mineral, and for this difference he found a name. III There seems to have been of late years a marked reaction, even among men of science, from the mechanistic conception of life as held by the band of scientists to which I have referred. Something like a new vitalism is making headway both on the Continent and in Great Britain. Its exponents urge that biological problems "defy any attempt at a mechanical explanation." These men stand for the idea "of the creative individuality of organisms" and that the main factors in organic evolution cannot be accounted for by the forces already operative in the inorganic world. There is, of course, a mathematical chance that in the endless changes and permutations of inert matter the four principal elements that make up a living body may fall or run together in just that order and number that the kindling of the flame of life requires, but it is a disquieting proposition. One atom too much or too little of any of them,--three of oxygen where two were required, or two of nitrogen where only one was wanted,--and the face of the world might have been vastly different. Not only did much depend on their coming together, but upon the order of their coming; they must unite in just such an order. Insinuate an atom or corpuscle of hydrogen or carbon at the wrong point in the ranks, and the trick is a failure. Is there any chance that they will hit upon a combination of things and forces that will make a machine--a watch, a gun, or even a row of pins?