i THE CHOICE OF AN EXAMPLE 63 



number of chromosomes and the rejection of a certain 

 quantity of chromatic substance. 1 Yet vegetables and 

 animals have evolved on independent lines, favoured 

 by unlike circumstances, opposed by unlike obstacles. 

 Here are two great series which have gone on 

 diverging. On either line, thousands and thousands 

 of causes have combined to determine the morpho 

 logical and functional evolution. Yet these infinitely 

 complicated causes have been consummated, in each 

 series, in the same effect. And this effect could 

 hardly be called a phenomenon of &quot; adaptation &quot; : 

 where is the adaptation, where is the pressure of 

 external circumstances ? There is no striking utility 

 in sexual generation ; it has been interpreted in the 

 most diverse ways ; and some very acute enquirers 

 even regard the sexuality of the plant, at least, as a 

 luxury which nature might have dispensed with. 2 But 

 we do not wish to dwell on facts so disputed. The 

 ambiguity of the term &quot; adaptation,&quot; and the necessity 

 of transcending both the point of view of mechanical 

 causality and that of anthropomorphic finality, will 

 stand out more clearly with simpler examples. At all 

 times the doctrine of finality has laid much stress on 

 the marvellous structure of the sense-organs, in order 

 to liken the work of nature to that of an intelligent 



o 



workman. Now, since these organs are found, in a 

 rudimentary state, in the lower animals, and since 

 nature offers us many intermediaries between the 

 pigment-spot of the simplest organisms and the in- 



1 P. Guerin, Les Connaissances actuelles sur la fecondation chez les pha- 

 nfrogames, Paris, 1904, pp. 144-148. Cf. Delage, UHe r&tite, 2nd edition, 

 1903, pp. 140 ff. 



2 Mobius, Eeitrdge zur Lehre &amp;lt;von der Fortpflanzung der Genvacfise, Jena, 

 1897, pp. 203-206 in particular. Cf. Hartog, &quot;Sur les phenomenes de re 

 production&quot; (Annte biologique, 1895, pp. 707-709). 



