THE ORIGIN OF FLOWERS 209 



caused by its feet in walking along the flower causes the appearance 

 of colouring matter, and the colour is likewise transmitted.' . . . ' As it 

 probes for honey it causes a flow of sweet sap to that part, and this 

 also becomes hereditary ! ' 



In this case, also, it is simply taken for granted that every 

 Httle passing irritation not only produces a perceptible efi'ect, but 

 that this effect is transmissible. In a later lecture we shall have to 

 discuss in detail the question of the inheritance of functional modi- 

 fications. It is enough to say here that, if this kind of transmission 

 really took place even in the case of such minute and transitory 

 changes, there could be no dispute as to the correctness of the 

 ' Lamarckian principle,' since every fairly strong and lasting irritation 

 could be demonstrated with certainty to produce an effect. When 

 a butterfly, floating freely in the air, sucks honey from a tube, the 

 irritation must be almost analogous to that caused by a comb lightly 

 drawn by some one through our hair, and this is supposed to effect 

 the gradual lengthening of the corolla-tube of the flower ! 



The secretion of honey, too, depends upon the persistent irritation 

 of the proboscis ! Then ' deceptive flowers,' like the Cypripedium we 

 have mentioned, could not exist at all, for they contain no honey, 

 although the proboscis of the bee must cause the same irritation in 

 them as in other orchids which do contain honey. This whole 

 'theory' of direct effect is, moreover, only a crude and apparent inter- 

 pretation, which explains the conditions only in so far as they can 

 be seen from a distance; it fails as soon as they are more exactly 

 examined ; aU the great differences in the position of the honey, its 

 concealment from intelligent insects, its protection from rain by 

 means of hairs, and against unwelcome guests by a sticky secretion, 

 the development of a corolla-tube which corresponds in length 

 to the length of the visiting insect's proboscis, the development of 

 spurs on the flower, in short, all the numerous contrivances which 

 have reference to cross-fertilization by insects remain quite uninteUi- 

 gible in the light of this theory — it is a mere ^)zs aller explanation 

 for those who continue to struggle against accepting the theory of 

 selection. 



