434 FERTILISATION OF FLOWERS. [1857. 



idea ('Nature,' June 4, 1874): — ''The aphorism, 'Nature 

 abhors a vacuum,' is a characteristic specimen of the science 

 of the middle ages. The aphorism, ' Nature abhors close 

 fertilisation,' and the demonstration of the principle, belong 

 to our age and to Mr. Darwin. To have originated this, and 

 also the principle of Natural Selection .... and to have 

 applied these principles to the system of nature, in such a 

 manner as to make, within a dozen years, a deeper impres- 

 sion upon natural history than has been made since Linnaeus, 

 is ample title for one man's fame." 



The flowers of the Papilionacese attracted his attention 

 early, and were the subject of his first paper on fertilisation.* 

 The following extract from an undated letter to Dr. Asa 

 Gray seems to have been written before the publication of 

 this paper, probably in 1856 or 1857 : — 



". . . . What you say on Papilionaceous flowers is very 

 true ; and I have no facts to show that varieties are crossed ; 

 but yet (and the same remark is applicable in a beautiful way 

 to Fumaria and Dielytra, as I noticed many years ago), I 

 must believe that the flowers are constructed partly in direct 

 relation to the visits of insects; and how insects can avoid 

 bringing pollen from other individuals I cannot understand. 

 It is really pretty to watch the action of a Humble-bee on 

 the scarlet kidney bean, and in this genus (and in Lathy rus 

 grandiflo7-us) the honey is so placed that the bee invariably 

 alights on that 07ie side of the flower towards which the spiral 

 pistil is protruded (bringing out with it pollen), and by the 

 depression of the wing-petal is forced against the bee's side 

 all dusted with pollen.f In the broom the pistil is rubbed 

 on the centre of the back of the bee. I suspect there is some- 



* Gardeners' Chronicle, 1857, p. 725. It appears that this paper was a 

 piece of "over-time" work. He wrote to a friend, "that confounded 

 leguminous paper was done in the afternoon, and the consequence was I 

 had to go to Moor Park for a week." 



\ If you will look at a bed of scarlet kidney beans you will find that 

 the wing-petals on the left side alone are all scratched by the tarsi of the 

 bees. [Note in the original letter by C. Darwin.] 



