Page:Popular Science Monthly Volume 16.djvu/823

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THE CRAYFISH.

THE CRAYFISH.[1]
By Professor E. RAY LANKESTER.

"COMMON and lowly as most may think the crayfish, it is yet so full of wonders that the greatest naturalist may be puzzled to give a clear account of it." These words from Von Rosenhof, who in 1755 contributed his share to our knowledge of the animal in question, are cited by Professor Huxley in the preface to the careful account of the English crayfish and its immediate congeners, which forms the latest volume of "The International Scientific Series." The book is not designed for "general readers," those somewhat luxurious but presumably intelligent persons for whom so much scientific knowledge is chopped and spiced at the present day. It is, as we gather from the author's statement, intended as an introduction to serious zoological study, for those who will turn over its pages, crayfish in hand, and carefully verify its statements as to details of structure with scalpel and microscope. To these and also to those who are already well versed in crustacean anatomy, the book will have great value and interest; to the latter more especially, as showing how in the careful study of one organism we are "brought face to face with all the great zoological questions which excite so lively an interest at the present day," and as an exhibition of that "method by which alone we can hope to attain to satisfactory answers of these questions."

A crayfish is treated in this volume from the point of view of "science," and in the first pages we have some excellent observations (recalling earlier remarks of the author's in the same sense) directed to clearing up that mystery which good people will insist on throwing around that ever-more-widely-heard term, "Common sense," says . Professor Huxley, "is science exactly in so far as it fulfills the ideal of common sense; that is, sees facts as they are, or, at any rate, without the distortion of prejudice, and reasons from them in accordance with the dictates of sound judgment. And science is simply common sense at its best, that is, rigidly accurate in observation, and merciless to fallacy in logic." In the preceding quotation. Professor Huxley is (in a legitimate and intelligible way) using the word "science" in place of "that quality of mental activity by which science is produced." Immediately afterward he speaks of science as the product of certain mental operations, in a passage which possesses great beauty while setting forth fundamental but neglected truths as to the source and scope of human knowledge. "In its earliest development knowledge is self-sown. Impressions force themselves upon men's senses

  1. The Crayfish: an Introduction to the Study of Zoölogy. By T. H. Huxley, F.R.S. New York: D. Appleton & Co.