Elementary Physiology i j^t 



editions. In it he wrote primarily for teachers and 

 learners in boys' and girls' schools, and selected from 

 the great bulk of knowledge and opinion called hu- 

 man physiology only the important and well-estab- 

 lished truths. So successful was he in his selection 

 that, notwithstanding the immense increase in know- 

 ledge since he wrote, the book still remains an adequate 

 and useful elementary treatise, and by this time must 

 have given their main knowledge of the human body 

 to hundreds and thousands of readers who otherwise 

 would have remained ignorant. 



The books of which we have been writing were ad- 

 dressed to the general public, but, in addition, Huxley 

 wrote several, of which three are specially important, 

 for those students who devote themselves specially to 

 anatomy. T/ic Crayfish, his famous volume in the 

 International Scientific Series, has been called by Pro- 

 fessor Howes, the assistant and successor of Huxley 

 at the Royal College of Science, " probably the best 

 biological treatise ever written." Many naturalists 

 have written elaborate monographs on single animals : 

 Lyonet worked for years on the willow caterpillar, 

 vStrauss Durckheim devoted an even minuter attention 

 to the common cockchafer, and the great Bojanus 

 investigated almost every fibre in the structure of the 

 tortoise. The volumes produced by these anatomists 

 were valuable and memorable, and occupy an hon- 

 oured place in the library of science, but Huxley's 

 aim was wider and greater. He showed how careful 

 stud}^ of one of the commonest and most insignificant 

 of animals leads, step by step, from every-day know- 

 ledge to the widest generali.sations and the mo.st diffi- 

 cult problems of zoology. He made study of a single 

 creature an introduction to a whole science, and taught 



