LECTURES. 37 
inside. It stands in the way of a bee seeking for honey, and the bee 
will very probably thrust his proboscis into the cup, but should he fail 
to do so, he will touch the outside of the stigma, which causes it to 
shut with a snap, and so prevents it from being touched by pollen 
from its own flower. 
Salvia (Sage) is chiefly remarkable for the enormous extent to 
which the connectives of the two anthers of each stamen have been 
developed. In S. pratenszs the stamen is quite short and the lower 
anther is abortive, and forms a round knob ; the connective is so long 
that the upper anther lies in the front part of the hood, and if a bee — 
strikes the knob, a shower-bath of pollen falls down on its back. In ~ 
an older flower the style opens in such a position as to come into con- — 
tact with the same part of the bee. In S. offcinadis, a simpler mechan- — 
ism produces the same result. 
The Germander Speedwell ( Veronica Chamedrys), another of the 
Scrophulariacee, is mostly fertilised by flies, an unusual occurrence in | 
blue flowers. A fly alights on the corolla, and seizing the widely 
diverging stamens as a support, draws them under its body, which 
is dusted with pollen in such a way as to cause cross-fertilisation when ~ 
it visits an older flower. 
These few examples must suffice, and now a few words in conclu-— 
sion. Firstly, the evidence we have accumulated is very contradictory. — 
We find that plants like columbine or sage, which have developed 
very elaborate mechanisms to ensure cross-fertilisation, and which 
have been rewarded by the possession of a graceful form and bright 
colours, are far less abundant than the buttercup or dovesfoot cranes- 
bill, which depend mainly on self-fertilisation. The true aim of an_ 
organism then is neither cross- nor self-fertilisation, but the greatest | 
possible increase in the number of its individuals. To this end self 
fertilisation, which is simple and certain, would seem to be the most 
direct means, but an occasional disturbance of its equilibrium seems 
necessary to keep up the vigour of every organism. This may be ob- § 
tained by the crossing of individuals which differ slightly from one @ 
another, or by a change of surroundings. When insects are plentiful 
the first method would be pursued, but should they fail, the flower 
will have to fall back on self-fertilisation (as has been the case wit 
bee orchid and groundsel), and the plant will only continue to flouris 
if it finds new ways of changing its conditions, such as disposal of it 
seeds by birds or wind, or transplantation by means of runners, 
finally, a development of new features which may prove attractive 
othet insects. and so secure cross-fertilisation once more. And ( 
