Transcriber’s notes
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Pages 401–729 and Plates III–VIII are in Volume II. Links to themmay not work with some reading devices.
LONDON:
PRINTED BY GILBERT AND RIVINGTON, LIMITED,
ST. JOHN’S SQUARE,
STUDIES IN THE THEORY
OF DESCENT
BY
DR. AUGUST WEISMANN
PROFESSOR IN THE UNIVERSITY OF FREIBURG
WITH NOTES AND ADDITIONS BY THE AUTHOR
TRANSLATED AND EDITED, WITH NOTES, BY
RAPHAEL MELDOLA, F.C.S.
LATE VICE-PRESIDENT OF THE ENTOMOLOGICAL SOCIETY OF LONDON
WITH A PREFATORY NOTICE BY
CHARLES DARWIN, LL.D., F.R.S.
Author of “The Origin of Species,” &c.
IN TWO VOLUMES
VOL. I.
WITH EIGHT COLOURED PLATES
London:
SAMPSON LOW, MARSTON, SEARLE, & RIVINGTON
CROWN BUILDINGS, 188, FLEET STREET
1882
[All rights reserved.]
The present work by Professor Weismann, wellknown for his profound embryological investigationson the Diptera, will appear, I believe, to everynaturalist extremely interesting and well deservingof careful study. Any one looking at the longitudinaland oblique stripes, often of various andbright colours, on the caterpillars of Sphinx-moths,would naturally be inclined to doubtwhether these could be of the least use to theinsect; in the olden time they would have beencalled freaks of Nature. But the present bookshows that in most cases the colouring can hardlyfail to be of high importance as a protection.This indeed was proved experimentally in one ofthe most curious instances described, in whichthe thickened anterior end of the caterpillar bearstwo large ocelli or eye-like spots, which give tothe creature so formidable an appearance thatbirds were frightened away. But the mere explanationof the colouring of these caterpillars isbut a very small part of the merit of the work.This mainly consists in the light thrown on thevilaws of variation and of inheritance by the factsgiven and discussed. There is also a valuable discussionon classification, as founded on charactersdisplayed at different ages by animals belongingto the same group. Several distinguished naturalistsmaintain with much confidence that organicbeings tend to vary and to rise in the scale, independentlyof the conditions to which they andtheir progenitors have been exposed; whilstothers maintain that all variation is due to suchexposure, though the manner in which the environmentacts is as yet quite unknown. At thepresent time there is hardly any question inbiology of more importance than this of thenature and causes of variability, and the readerwill find in the present work an able discussionon the whole subject, which will probably leadhim to pause before he admits the existence of aninnate tendency to perfectibility. Finally, whoevercompares the discussions in this volume withthose published twenty years ago on any br