The address of the President of the British Association, delivered at Liverpool, illustrates in a very remarkable manner the practical utilities of Science. One of the largest and profoundest questions with which Science deals is that of the relationship of life and matter, yet the discussion of that question brings us into immediate contact with those terrible epidemics which scourge all organised beings from the insect up to man. Dr Huxley reviews the progress of scientific discovery in its inquiry into the genesis of life, and pronounces a strong opinion in favour of the theory that only life begets life, and against the theory that life can ever spring from death. With true scientific modesty, he declines to assert that at no period in this planet's history has living protoplasm ever been evolved from matter which was not alive, but he insists that no such evolution has ever been shown to have taken place within our experience or observation. So far as that experience goes, an impassable line exists between living matter and matter which is not alive, and the living never comes out of the dead.

The experiments which demonstrate this scientific truth lead us into the realm of inquiry with which Dr Tyndall familiarised us early in the year in his striking lecture on "Dust and Disease." Dr Tyndall's experiments completed the demonstration of the doctrine of Biogenesis - that is, the doctrine that life springs only from life, and never from dead matter - by showing first that ordinary air is full of particles, which are very often the floating germs of animal and vegetable forms; and secondly, that filtration through cotton wool allows only physically pure air to pass. These minute forms, floating in the dust which the sunbeam reveals, are the origin of all the life which putrefaction and other forms of fermentation produce. It is this minute life, sometimes in the form of fungi, sometimes in that of minute animalcule, which is the cause of infectious and contagious disease. The terrible disease called Pebrine, which has been so fatal to silkworms, has been demonstrated by M. Pasteur to be caused by the development and multiplication of minute organisms in the body of the silkworm. These organisms pass from one silkworm to another by infection, by contagion, and by transmission in the egg, and develop into a disease which greatly corresponds to the cholera in man.

M. Pasteur has consequently been able to suggest a method of extirpating the f disease, which has been completely successful wherever it has been carried out. A similar discovery bad previously been made as to the cause of the Grape disease, and Science has thus saved to France the silk crop and the Grape crop, and shown the way to their future safety. But even greater results than these may be expected from these investigations. The cholera and the scarlet fever are probably both due to minute organisms which float in air or water, and being received into the body, develop and propagate there. The germ theory of life is leading us to so complete a knowledge of epidemic diseases, that Professor Huxley is able to say that so far as scarlet fever is concerned, "the facts which I have placed before you must leave the least sanguine without a doubt that the causes of this scourge will one day be as well understood as those of Pebrine are now, and that the long-suffered massacre of our innocents will come to an end." It is thus that science and civilisation go hand in hand together.

We study Nature to subdue her, stoop to humble observation of her ways that we may conquer her; and Science, which is only knowledge of her laws, makes us free of her kingdom. - Daily News.