VARIATION IN ANIMALS AND PLANTS 171 
Variation in Animals and Plants. By H. M. Vernon, M.A., M. 
International Scientific Series, vol. lxxxviii. Pp. 415, 5 figures 
and 25 diagrams. 19038. Price 5s. Kegan Paul & Co. 
WuHE arwin was elaborating the tir tn be Origin and 
Descent, he recognized the import of many problems bearing on 
the general ee on: implied by the acceptance of the theory of 
Evolution (as a working hypothesis) to the elucidation of the con- 
tributory factors, which were collaterally invo "a ens poe 
would be shed on the causes of the diverse influences which not 
only favour continuous variation but also check it. Such, indeed, 
has happened. Neo-Lamarckism, Weismannism, Panmixia, and 
Genepistasis are examples of the labels which have been ‘attached 
u modi 
they have not sometimes obscured it. ateson’s Materials for 
the Study of Variation was the precursor a many essays, dealing 
with the factors of organic evolution, in which distinct lines of 
investigation have been followed up; and it succeeded in dra awing 
attention to the important work which had been done in Germany, 
with the Bred acceptance and ready assimilation of Darwin’s 
conclusio 
The lat test addition to the “ alee iy ol tin 
will enhance the interest of the set of volumes, devoted to the 
exposition of many aspects of ate science, rnasdpafated several 
ears ago with Tyndall’s Forms of Water. The author gives an 
account of the subject of Variation, in a well-digested gees of 
recent investigations, leading from the facts of Variation up to 
causes, and the apparent laws which govern them, proceeding then 
to discuss Variation in its relation to Evolution. No apology is 
needed for contributing to the interest of the volume by including 
the author’s own researches. The incorporation of the results of a 
series of ‘ivesgatains, siaiiaite bearing on the subject, and free 
from dogmatic inferences, even in an or y text-book, adds 
pois iderably to its value; the more so when no previous work 
exactly covers the same groun 
the lull in controversy, and the passive but discriminating 
acquiescence, which followed Darwin’s later works, the ree ’ 
a lethargic anticlimax was averted, strange say, by the 
ticians, who, b Segoe measurements, an e eres it oe 
‘Prof. Karl Pearson bade the credit of adel te ie the im- 
portance of meristic as distinguished from substantive variation. 
r. Vernon is considerate enough to dispense with 1 algebraical 
formulas of the higher mathematies in expressing the co-ordinating 
