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- REVIEWS AND BOOK NOTICES. 223 
writers to himself—changes not only involving nomenclature and 
the rest of the machinery, but also profoundly affecting methods of 
study. It is too early to decide whether the modification was sim- 
ply the inevitable swinging back of a pendulum that has reached 
its limit, or whether it was effected—at any rate, hastened — by 
Mr. Allen’s instrumentality. In the latter event, and if the late 
revulsion proves to be, as it apparently is, a real reform, Mr. 
Allen’s conspicuous connection with the progress of the science at 
that particular time is to be regarded as singularly fortunate.— 
E. C. 
INTERMEMBRAL Homotoares.* — Since it is not reasonably pos- 
sible to do justice to this remarkable paper within the limits to 
which we are confined on this occasion, we must be content to in- 
dicate its nature and scope. This restriction is perhaps the less to 
be regretted because, as some few of our readers may be aware, 
our own studies of the same subject have run too nearly parallel 
with Prof. Wilder’s for us to have entirely escaped a bias of judg- 
ment unfavorable to impartial criticism ; and because we would not 
even seem to seize an opportunity that the office of reviewer affords 
of arguing in favor of views that both the author and ourselves 
desire should be left to stand or fall upon their own merits. 
ing criticism can only be expected from those who differ, not thoat 
who agree. We are satisfied of the soundness of Prof. Wilder’s 
main views of the vertebrate homologies ; and if we are at present 
unprepared to go with him as far as he has gone, this is chiefly 
because he appears to have pushed past a certain Rubicon that 
separates the safe logic of observation from the possibly fallible 
results of speculation. If we were urged to specify what we be- 
lieve to be a misconception under which our learned friend labors, 
we should say it were this, as gathered from his collateral writings ; 
that no mental abstraction, whether moral, esthetic or purely 
intellectual, can be formed, unless a corresponding material em- 
iment exists; and that consequently conception of an idea 
implies that it has some real physical expression. But there is 
reason to believe in the existence of a class of ideas, conventionally 
designated, as fanciful, to which this hypothesis has no proven 
application. One of the clearest and strongest points of the paper 
“© Intermempral Homologies: The Correspondence of the Anterior and 1 Ae 
Limbs of a By Burt G. Wilder, S. B., M. D., ete., Proc. Bost. Soc. N. H. 
xiv, p. 154, et 
