i88o.] 
Analyses of Books. 
587 
interpreted, not merely by the jealousy and pseudo-conservatism 
of the old, but also by the rashness and sciolism of the young 
expositions of its evidences, its true character and its tendencies 
will be needed. 
The German translator has performed his task ably and tho- 
roughly. 
A Treatise on Comparative Embryology. By F. M. Balfour, 
F.R.S. In two volumes. Vol. I. London : Macmillan 
and Co. 
We have here a complete and systematic treatise on one of the 
most important branches of Biology. Since the evolutionist 
theory of the organic world has become the accepted view of the 
majority of minds capable of judging, Embryology has under- 
gone a remarkable increase in its interest and in the importance 
of its revelations. The resemblance of the embryonic and larval 
stages of the higher animals to the lower forms of their respective 
groups had long excited the attention of philosophical zoologists, 
and is now recognised as supplying a most valuable body of 
evidence in favour of the so-called doctrine of Descent, and 
against that of mechanical or contract Creation. For want, 
however, of such knowledge as the work before us will furnish, 
this parallelism between the evolution of the individual and of 
the group, if not overstrained, has been somewhat distorted. 
The higher embryo does not exactly resemble the lower adult. 
Nor would such close resemblance, if it existed, be in harmony 
with the requirements of the modern theory, which regards all 
organic groups as formed by a series of branchings out from one 
common stem. The human embryo, at a certain stage of growth, 
approximates very closely to those of apes, and even of carni- 
vorous animals. But as the species approach maturity they 
diverge more and more from each other, so that the child has 
never passed through a stage resembling that of the mias or the 
do°\ What really does occur, as stated by the author, is this : — 
“ Each organism reproduces the variations inherited from all its 
ancestors at successive stages in its individual ontogeny, which 
correspond with those stages at which such variations appeared 
in its ancestors;” and to the law, as thus stated, we do not see 
that any exception need be taken. 
But whilst the enhanced importance of embryology and the 
abundance of researches lately undertaken render a work like 
that before us desirable, they place, as the author fully recognises, 
serious difficulties in the way of its execution. He refers to the 
recent appearance of “ a large number of incomplete and con- 
tradictory observations and theories.” He might have mentioned 
that some of these researches have been undertaken by men 
