THE CRAYFISH. 789 



THE CRAYFISH* 



By Pkofessor E. EAY LANKESTEE. 



''/~^OMMO]^ and lowly as most may think the crayfish, it is yet so 

 vy 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 pre- 

 sumably 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 in- 

 terest ; to the latter more esj^ecially, 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 " sci- 

 ence," and in the first pages we have some excellent observations (re- 

 calling 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, with- 

 out 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 w^hich science is pro- 

 duced." Immediately afterward he speaks of science as the product 

 of certain mental operations, in a passage which possesses great beauty 

 while setting forth fundamental bxit neglected truths as to the source 

 and scope of human knowledge. " In its earliest development knowl- 

 edge is self-sown. Impressions force themselves upon men's senses 



* The Crayfish : an Introduction to the Study of Zoology. By T. H. Huxley, F. R. S. 



New York : D. Appleton & Co. 



