NECTARIES. 263 



mity to the stigma, should yet not fertilise the latter, 

 we must discuss the manner in which the nectar is 

 produced, and placed so as not only to attract the 

 insect, but also force it, while taking its repast, to 

 deposit pollen, brought upon its body, on to the 

 stigma. 



It is more convenient than accurate to speak of 

 "honey-yielding plants," and of bees gathering honey; 

 for the fluid secreted by the flower is unlike honey 

 in more particulars than one, and is denominated 

 nectar, while the part by which it is yielded is called 

 a nectary. Although it is certain that the character 

 of the secretion varies considerably in different plants, 

 analysis has shown that, in a large proportion of 

 instances, the sugar it contains is identical with that 

 derived from the cane or beet-root, while the sugar 

 of honey is similar to that of the grape. From what 

 has already been said of the glandular and tongue 

 structures of bees (pages 81 and 101), it is clear 

 that a salivary secretion is added to the gathered 

 nectar, and that this, like the saliva in our own case, 

 converts the cane into grape sugar; and probably 

 also, as with ourselves, this is an initial step in 

 assimilation, since cane sugar is actually poisonous 

 to the blood, while grape sugar acts within it as a 

 normal producer of heat and force. Many flowers 

 are especially contrived for fertilisation by moths 

 and butterflies, and there is strong reason for sup- 

 posing that these latter insects produce exactly the 

 same alteration — technically, " inversion " of the sugar 

 of nectar — as our bees. 



From what we know of the chemical changes occur- 



