THE WEB OF LIFE 277 



its own use, and would secrete nectar were there no bees. 

 The nectaries are manufactories where cane-sugar (due to 

 the starch made in the leaves) is worked up and stored — 

 usually for the fruits and seeds. The drops that are sweated 

 out, as night falls, from the nectaries never contain more 

 than a small part of the sugar of the nectaries ; they cor- 

 respond to water-drops elsewhere, except that they are more 

 or less rich in sugar ; if insects do not suck them up they 

 are re-absorbed in due course. This appears to be a very 

 effective objection up to a certain point. It shows that 

 the primary significance of the nectaries is for the plant 

 itself. We wish to point out, however, a rule in scientific 

 method which has its apphcation here, namely, that one 

 must be careful not to mix up problems of origin with 

 problems of subsequent evolution. Bonnier's evidence that 

 the primary significance of nectaries is for the plant itself, 

 is not inconsistent with the view that bees and other 

 insects may have had something to do with the evolution of 

 these organs, e.g. in determining their precise position. 

 It remains a fact that bees tap them, and it is probable 

 that these visits of bees have, in the course of ages, had 

 some selective influence on the plants. 



In regard to the fragrance of flowers the case is just a 

 httle different. It cannot be said that the fragrance as 

 such is of direct use to the flowers. It may be a quite 

 incidental property of chemical substances which are 

 important in the metabohsm of the plant. But in the 

 same way it may be argued that the sweetness of nectar is 

 not as sweetness of direct use to the plant. The sugar need 

 not have been sweet, and the chemical substances referred 

 to need not have been aromatic. As it appears to us, clear- 

 ness comes when we separate the two problems — of origin 



