president's address. 
28 5 
colour or species, and indeed one of the chief pre-occupations of 
the hive, is the methodical bestowal of their pollens in their store- 
rooms, in strict accordance with their origin and colour.” 
Where then must we seek the guide which directs the flight of 
the Bee on her second visit to the flowers? Is it the conspicuous 
corolla or the pollen covered anthers ? or is it the remembrance of 
the odours only ? by which she can 
“ With conscious truth retrace the mazy clue 
Of varied scents which charmed her as she flew.” 
If we watch the Bees in our gardens flying from flower to flower, 
apparently without method or choice, we shall perhaps wonder 
whether too much has not been made of this “flower fidelity.” 
What are other benefits that the plants derive from odours which 
they emit? They gain protection from herbivorous animals; in some 
cases the smell renders the leaves distasteful, and in others the 
scent gives warning that the plant, though not unpleasant, is 
harmful : this is the case with the Thorn-Apple, Hemlock, and 
Deadly Nightshade. The warning to avoid these seems to be given 
by the olfactory nerve. The scent of the stem is also a protection 
against the depredations of larvae, as with many of the Conifene, 
and with the Sweet Flag, which we cannot believe to have been 
developed from a Common Flag into an odorate Calamus for the 
benefit of Abbots and Aldermen, who loved to strew their halls 
with its fragrant leaves. 
The researches of Professor Tyndall made known to us the 
action of odours on radiant heat, and he published a table showing 
the relative potency of various perfumes as intercepters of radiation ; 
from this it appears that the odour of oil of Cloves exercises about 
thirty times the action of the air, of Lavender sixty times, and 
that of Spikenard up to three hundred and fifty times. This 
discovery suggested another advantage to be derived by plants from 
their perfumes ; in hot and dry countries the secretion of strong 
scented ethereal oils, surrounds the plant with an invisible though 
most efficient shield against the baneful effects of radiant heat, and 
we observe that Spikenard which comes from a country where such 
protection is much needed, is one of the most powerful absorbents 
