EARLY THEORIES. 3 



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 m^de 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 Heiden- 

 hain, 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 physio- 

 logists 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 



