180 THE EVOLUTION THEORY 



have been blossoms, but there would have been no flowers — that is to 

 say, blossoms with large, coloured, outer parts, with fragrance, and with 

 nectar inside, unless the blossoms had been sought out by insects 

 during the long ages. Flowers are adaptations of the higher flowering 

 plants to the visits of insects. There can be no doubt about that now, 

 for — thanks to the numerous and very detailed studies of a small 

 number of prominent workers — we need not only suppose it, we can 

 prove it with all the certainty that can be desired. The mutual 

 adaptations of insects and flowers afford one of the clearest examples 

 of the mode of operation and the power of natural selection, and the 

 case cannot therefore be omitted from lectures on the theory of 

 descent. 



That bees and many other insects visit flowers for the sake of the 

 nectar and pollen has been known to men from very early times. 

 But this fact by itself would only explain why adaptations to flower- 

 visiting have taken place in these insects to enable them, for instance, 

 to reach the nectar out of deep corolla-tubes, or to load themselves 

 with a great quantity of pollen, and to carry it to their hives, as 

 happens in the case of the bees. But what causes the plants to 

 produce nectar, and offer it to the insects, since it is of no use to 

 themselves? And further, what induces them to make the pillage 

 easier to the insects, by making their blossoms visible from afar 

 through their brilliant colours, or by sending forth a stream of 

 fragrance that, even during the night, guides their visitors towards 

 them ? 



As far back as the end of the eighteenth century a thoughtful 

 and clear-sighted Berlin naturalist, Christian Konrad Sprengel, took 

 a great step towards answering this question. In the year 1793 he 

 published a paper entitled ' The Newly Discovered Secret of Nature 

 in the Structure and Fertilization of Flowers V m which he quite 

 correctly recognized and interpreted a great many of the remarkable 

 adaptations of flowers to the visits of insects. Unfortunately, the 

 value of these discoveries was not appreciated in Sprengel's own 

 time, and his work had to wait more than half a century for 

 recognition. 



Sprengel was completely dominated by the idea of an all-wise 

 Creator, who ' has not created even a single hair without intention/ 

 and, guided by this idea, he endeavoured to penetrate into the 

 significance of many little details in the structure of flowers. Thus 

 he recognized that the hairs which cover the lower surface of the 



1 Das neu-entdeckte Geheimniss der Natur im Bau u. der Befruchtung der Blumen, Berlin, 

 1793- 



