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The present work by Professor Weismann, who is well known for his profound embryological investigations on the Diptera, will appear, I believe, to me to every naturalist extremely interesting, & well deserving of careful study. Anyone looking at the longitudinal & oblique stripes of various & often bright colours on the caterpillars of Sphinx-moths, would naturally be inclined to doubt whether they could be of the least importance use to these animal,— have in the olden time they wo would have been called freaks of Nature. But after reading the present book book with its excellent coloured drawing shows how important that in most cases the colouring can hardly fail to be very important of high importance as a protection. This indeed was proved in experimentally in one of the most curious instances described, in which the thickened anterior end of the caterpillar bears two large ocelli— or large eye-like spots, by which creature gives to the creature so formidable an appearance that it frightened away birds were frightened away. But the mere explanation of the colouring of the caterpillars is but a very small part of the merit of the work. This mainly consists in the light thrown

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by the facts which are given & discussed on the laws of variation & of inheritance. There is also a more valuable discussion on Classification, No subject at the present times is more as founded on characters displayed at different ages.

Several distinguished naturalists, such as that Nägeli, maintain with much confidence that organic beings tend to vary & to become rise in the scale, merit independently of the conditions to which they & their progenitors have been exposed; whilst others maintain that all variation is due to such exposure, though the manner in which the condition environment acts is as yet quite unknown. At the present time & there is perhaps hardly any question subject at present in biology of more importance than the of the nature & causes of variability, & the reader will find in the present work a most able discussion on the whole subject, & this  will probably cause lead him to pause before he admits the existence of admittedly an innate innate tendency towards varying to perfectibility.

Finally, he who believes in evolution whoever compares the work but not discussed or infer in this volume with those published 20 years ago on any branch of Natural History will see with satisfaction how wide & rich a field of for study is has been opened up by through the principle of Evolution; & which without the light the shed by this principle, would for long or for ever have remained barren.

[in another hand:] Preface for Weismann

1878