But it is pretty clear that there must have been some change between yesterday and to-day. Not in vain has general science and biology itself made the progress which we know has been made since the Renaissance, and especially during the course of the nineteenth century. The old theories have been compelled to take new shape, such parts as have become obsolete have been cut away, another language is spoken—in a word, the theories have become rejuvenated. The neo-animists of our day, Chauffard in 1878, von Bunge in 1889, and more recently Rindfleisch, do not hold exactly the same views as Aristotle, St. Thomas Aquinas, or Stahl. Contemporary neo-vitalists, physiologists like Heidenhain, chemists like Armand Gautier, or botanists like Reinke do not between 1880 and 1900 hold the same views as Paracelsus in the fifteenth century and Van Helmont in the seventeenth, as Barthez and Bordeu at the end of the eighteenth, or as Cuvier and Bichat at the beginning of the nineteenth century. Finally, the mechanicians themselves, whether they be disciples of Darwin and Haeckel, as most biologists of our own time, or disciples of Lavoisier, as most physiologists of the present day, have passed far beyond the ideas of Descartes. They would reject the coarse materialism of the celebrated philosopher. They would no longer consider the living organism as a machine, composed of nothing but wheels, springs, levers, presses, sieves, pipes, and valves; or again of matrasses, retorts, or alembics, as the iatro-*mechanicians and would-be chemists of other days believed.
All that is changed, at any rate in form. If we look back only thirty or forty years we see that the old
