INTKODUCTORY 21 



an organ can be transmitted by inheritance to the succeedino- 

 generation. We shall have to discuss this question in detail at a later 

 stage, and I shall only say now that opinions as to whether this is 

 possible or not are very much divided. I myself doubt this possi- 

 bility, and therefore cannot admit the validity of the Lamarckian 

 evolutionary principle in so far as it implies the directly transformino- 

 effect of the functioning of an organ. But even if we recognize the 

 Lamarckian factor as a vera causa, it is easy to show that there are 

 a great many characters which it is not in a position to interpret. 

 Many insects which live upon green leaves are green, and not a few 

 of them possess exactly the shade of green which marks the plant on 

 which they feed ; they are thus protected in a certain measure from 

 injuries. But how could this green colour of the skin have been 

 brought about by the activity of the skin, since the colour of the 

 surroundings does not usually stimulate the skin to activity at all 1 Or 

 how should a grasshopper, which is in the habit of sitting on dry 

 branches of herbs, have thereby been incited to an activity which 

 imparts to it the colour and shape of a dry twig ? Just as little, or 

 perhaps still less, can the protective green colour of a bird's or insect's 

 eggs be explained through the direct influence of their usually green 

 surroundings, even if we disregard the fact that the eggs are green 

 when they are laid — that is, before the environment can have had any 

 influence on them. 



The Lamarckian principle of modification through use does not, 

 in any case, nearly suffice as an interpretation of the transformations 

 of the organic world. It must be allowed that Lamarck's theory 

 of transformation was well founded at the time when it was 

 advanced ; it not only attacked the doctrine of the immutability of 

 species, but sought for the first time to indicate the forces and 

 influences which must be operative in the transformations of species ; 

 it was therefore well worth careful testing. Nevertheless it did not 

 divert science from its chosen path ; very little notice was taken of it, 

 and in the great Cuvier's chronicle of scientific publications for 1809, 

 not a syllable is devoted to Lamarck's book, so strong was the 

 power of prejudice. 



But, although the new doctrine was thus ignored, it did not 

 altogether fall to the ground ; it glimmered for a while in Germany, 

 where it found its champions in the ' Naturphilosophie ' of the time, 

 and especially in Lorenz Oken, a peasant's son, born at Ortenau, near 

 Oftenburg, in 1783. 



Oken professed views similar to those of Erasmus Darwin, 

 Treviranus, and Lamarck, though they were not clothed in such 



