VI
PREFACE.
and the most difficult problems of zoology; and, indeed, of biological science in general. It is for this reason that I have termed the book an “ Introduction to Zoology.57
For, whoever will
follow its pages, crayfish in hand, and will try to verify for himself the statements which it contains, will find himself brought face to face with all the great zoological questions which excite so lively an interest at the present day; he will understand the method by which alone we can hope to attain to satisfactory answers of these questions; and, finally, he will appreciate the justice of Diderot’s remark, u
II faut etre profond dans hart on dans la science
pour en bien posseder les elements.77 And these benefits will accrue to the student whatever shortcomings and errors in the work itself may be made apparent by the process of verification. u
Common and lowly as most may think the cray¬
fish,77 well says Eoesel von Bosenhof, “it is yet so full of wonders that the greatest naturalist may be puzzled to give a clear account of it.77
But only
