20 DARWINISM STATED BY DARWIN HIMSELF. 



of self-fertilization, through the combined aid of the 

 weight of the pollen-mass and the vibration of the flower 

 when moved by the wind. Every gradation between 

 these two states is possible — of which we have a partial 

 instance in 0. aranifera. 



Again, the elasticity of the pedicel of the pollinium 

 in some Vandece is adapted to free the pollen-masses from 

 their anther-cases ; but, by a further slight modification, 

 the elasticity of the pedicel becomes specially adapted to 

 shoot out the pollinium with considerable force, so as to 

 strike the body of the visiting insect. The great cavity 

 in the labellum of many Vandece is gnawed by insects, 

 and thus attracts them ; but in Mormodes ignea it is 

 greatly reduced in size, and serves in chief part to keep 

 the labellum in its new position on the summit of the 

 column. From the analogy of many plants we may in- 

 fer that a long, spur-like nectary is primarily adapted to 

 secrete and hold a store of nectar ; but in many orchids 

 it has so far lost this function that it contains fluid only 

 in the intercellular spaces. In those orchids in which 

 the nectary contains both free nectar and fluid in the 

 intercellular spaces, we can see how a transition from the 

 one state to the other could be effected, namely, by less 

 and less nectar being secreted from the inner membrane, 

 with more and more retained within the intercellular 

 spaces. Other analogous cases could be given. 



Although an organ may not have been originally 

 formed for some special purpose, if it now serves for this 

 end, we are justified in saying that it is specially adapted 

 for it. On the same principle, if a man were to make a 

 machine for some special purpose, but were to use old 

 wheels, springs, and pulleys, only slightly altered, the 

 whole machine, with all its parts, might be said to be 

 specially contrived for its present purpose. Thus through- 



