IN BORNEAN FORESTS [chap. 



of aquatic, land, desert,and forest plants, but also the infinite number 

 of modifications in floral organs which carry the impression of 

 stimuli exerted by insects. To the action of environment I attribute 

 also the cases of mimicry ; and I have extended my theory even 

 further, holding that moral impressions, and especially individual 

 volition, have exercised a great influence in the evolution of organ- 

 isms. 1 



It is only by admitting a pre-established plan that the existence 

 of certain forms and certain colours in some animals can be accounted 

 for. And this pre-established plan in the case of certain creatures 

 may have had its origin in the desire to attain a given end ; a desire 

 often caused by want or necessity, but at times by a love for the 

 beautiful, by pleasure, vanity, fear, or any of the many passions 

 and desires which agitate organized beings. For the genesis of 

 species to have taken place in accordance with the above theory, it 

 is necessary to assume that organisms possessed an inclination to 

 vary, or to allow themselves to be influenced by stimuli, one might 

 say almost without direct need, and in a manner precisely contrary 

 to that which occurs at the present time when individuals and 

 species do not vary, or, rather, cannot adapt themselves to new 

 conditions of existence, even when the need exists. 



It is, nevertheless, not impossible that in some instances certain 

 forms may have made their appearance suddenly, and may quite as 

 suddenly have adapted themselves to a new condition of the environ- 

 ment. This is the hypothesis of " Neogenesis," as it has been called 

 by Professor Mantegazza, in favour of which there are fewer facts 

 than for any other hypothesis of the kind. And yet it is the one 

 which has the most attractions for me. If we accept this hypo- 

 thesis it becomes quite unnecessary to admit a continuous deriva- 

 tion of organisms one from the other by slow modifications ; because 

 the connecting links which yet exist, or are revealed by palaeontology, 

 would be the result of hybridism between two prototypes of sudden 

 formation, whose reproduction was not impeded because it had no 

 force of heredity to contend with. 



The essence of my hypothesis consists in the argument that the 

 power of heredity is so great at the present period as to render varia- 

 tion in living organisms very feeble, if not impossible ; that conse- 

 quently adaptation to surrounding conditions is now all but nil ; and 

 that for this reason any modifications which may affect the individual 

 during life are not transmitted to its progeny. On the other hand, 

 in far distant geological times, adaptability to surroundings and 

 sensitiveness in reaction to stimuli must have been greater the 

 further back the epoch during which such influences were active. 



1 Cf. Beccari. " Le Ca panne ed i Giavdini dell 'Amblyornis inomata" ; 

 in Annali del Museo Civico di Genova, vol. ix. p. 382 (1877). 



214 



