192 HABIT AND INTELLIGENCE. [chap. 



of tlie two to say that this last statement is proved ; but it certainly 

 sources, receives strong confirmation from the facts that Darwin 

 has collected, and on which he justly lays great stress, 

 Herma- Concerning the fertilization of hermaphrodite organisms, 

 pluodite Many of these, as land-mollusca and earth-worms, have 

 ' the male and the female organs so placed with respect to 

 each other, that they cannot fertilize themselves, hut pair, 

 like animals with the sexes on distinct individuals. And 

 though many hermaphrodite animals do habitually fertilize 

 themselves, yet Darwin states, on Huxley's authority as 

 well as his own, that among known animals there is not 

 a single instance of the female organs being out of the 

 reach of the spermatozoa of another individual occasion- 

 ally entering. No terrestrial animal is known to fertilize 

 itself, and among aquatic species the spermatozoa may be 

 and plants, Carried in currents of water. ^ With respect to plants, the 

 °°* ^'^™y® evidence is even more remarkable and more decided. Most 



seli-terti- 



lizing. flowers are hermaphrodites ; and when the remarkable dis- 

 covery of the sexuality of flowers was first made, it was 

 naturally supposed that each flower was fertilized by its 

 own pollen. But Darwin has shown that in many cases 

 this is impossible, in consequence of the stamens and 

 pistils coming to maturity at different times ; ^ and there 

 are some instances of reciprocally dimorphic species of 

 plants — that is to say, plants bearing two kinds of flowers, 

 each of which contains both stamens and pistils ; but the 

 pistils of each form can be properly fertilized only by the 

 Agency of pollen of the other.^ Insects are the principal agents in 

 fertl^izino- Carrying pollen from one flower to another ; and it is 

 flowers. Darwin's belief that flowers have been endowed with their 

 bright colours (and, if so, no doubt with their nectar also) 

 for the purpose of attracting insects.* Insects are useful, 



1 Origin of Species, p. 113. = i^i^i pp_ m^ 325. 



3 Ibid. p. 320. 



* Ibid. ]). 239. " I have come to this conclusion," he says, " from 

 finding it an invariable rule that when a flower is fertilized by the wind, 

 it never has a brightly-coloured corolla. Again, several jjlants habitually 

 produce two kinds of flowers ; one kind open and coloured, so as to attract 

 insects, the other kind closed and not coloured, destitute of nectar, and 

 never visited by insects." 



