CH. xxxvm. ROBERT BROWN. 417 



ready to receive it. He afterwards found that in the cypress- 

 spurge exactly the opposite takes place. In this plant the 

 stigma is ready first, and the insects bring pollen from older 

 flowers, and the seeds form in the young flower before its 

 own stamens are ripe. 



From these facts Sprengel came to the conclusion that it 

 is an advantage to a flower to use other pollen than its own ; 

 and that the colours and shape of the flowers, and the honey 

 they secrete, are all adapted to attract the visits of insects 

 for this purpose. He also pointed out that flowers which 

 are not visited by insects are generally very insignificant, but 

 that they have large quantities of pollen-dust, so that it may 

 be carried by the wind. 



Sprengel looked upon all these adaptations as produced 

 at the creation of the plant or insect in order to secure that 

 they should be useful to each other. But, as we shall see' 

 in Chapter XLII., there is now every reason to believe that 

 they have been gradually perfected, by the flower adapting 

 itself to the visits of some particular insect which can per- 

 form for it the work it needs. 



Structural and Physiological Botany Robert 

 Brown, 1773-1858. The beautiful study of the relation 

 between insects and flowers is more easy to understand, but 

 certainly not more important, than the investigations into the 

 structure and life of plants which have been carried on in 

 the present century. Ever since the time of Malpighi and 

 Grew the improvement of microscopes and the examination 

 of minute parts of plants had been progressing ; and Mirbel 

 (1776-1854) in France, and Moldenhauer (1766-1827) 

 in Germany, together with many others, had greatly added 

 to our knowledge of the structure of the cells and 

 tissues of plants, the growth of stems, and the formation of 

 seeds. Grew had already pointed out in 1672 that the outer 



