138 Notices of Booh. [January, 
showing in a multitude of cases the various agencies by which 
“ unbidden guests ” are kept aloof. The author puts forth his 
work as a “ small contribution ” to the solution of one of the ques- 
tions underlying the theory of natural selection. He complains 
that the phrase “ the preservation of advantageous varieties ” is 
often misused, and he recommends that instead of indulging in 
vague generalities on this preservation, we should solve the ques- 
tion at issue by the experimental method.” No one can accuse 
him of neglecting to follow out his own advice. In his chapter 
on the advantages which accrue to the plant from bearing 
flowers, and especially from certain conformations of parts of 
the flower, we note that the word “biology” is used in a novel 
and, we fear, in a misleading sense, It generally signifies the 
entire science of living beings, but here we find it limited to 
“ the determination of the functional significance of morpho- 
logical characters. Dr. Kerner remarks very truly, “ it is rare 
that any part of a plant is so shaped as to be suitable for the 
attainment of but one end,” and he complains that naturalists 
have overshot the mark by trying to explain everything by the 
relation between the shape of the flower and that of the animals 
who visit it. In a special chapter he shows what inseCts and 
other animals are calculated to frustrate rather than subserve 
fertilisation, whether by destroying the flower, by consuming the 
neCtar without rendering the desired services in return, or by 
preventing the visits of bees, moths, &c. Among such intruders 
a prominent part is played by ants, earwigs, and small beetles. 
Wingless inseCts are of little service, since, even when they leave 
a flower laden with pollen, they cannot reach the flowers of a 
second stem of the same species until after a longjourney and a 
proportionately long lapse of time. 
The means of protection met with in different flowers against 
unbidden guests are explained in succession. Among these we 
find the secretion of distasteful substances, the hindrance of 
access by water, by viscid secretions, by prickles, hairy forma- 
tions, by the diversion of visitors to other parts. The whole 
work forces upon our notice that constant strife which, whether 
we like it or not, must be admitted as pervading all nature. The 
flower seeks, as it were, to obtain the services of animals at the 
lowest market price. The animal, on the other hand, seeks to 
take the pay without doing the work, as when bees bite a side 
entrance into a flower so as to steal the neCtar without effecting 
the desired exchange of pollen. Amidst such contrivances and 
counter-contrivances, every improvement on the one side being 
met by some fresh stratagem — if we may so term it — on the 
other, the notion of the “ perfection ” of every species, as incul- 
cated by the old school of natural history, does not show to 
advantage. It reminds us of an old work in which the writer 
gave instructions for the “ successful attack triumphant defence 
of any given fortress.” 
