xvlii PREFACE 



statements serve as refreshers and enable the student to follow the 

 thought more readily and more eflFectively. The writer has come to 

 regard the subject matter of the fourth chapter, Taxonomy, as very 

 important in the developing of the course; he has always been aided 

 in the presentation of this subject by teaching collections and ap- 

 propriate charts. In emphasizing the various forms and their posi- 

 tion some of the rules of capitalization have been violated in this 

 chapter. Moreover, in order to assist the reader in locating quickly 

 such subject matter as relates to Man, the word has been capitalized 

 throughout the volume. 



Any text book of this sort must of necessity consist largely of a 

 compilation, for no new facts and no new principles are to be pre- 

 sented. For illustrative examples frequent recourse has been made 

 to original papers for which no acknowledgment of source has been 

 made. Credit for original work is largely the concern of the profes- 

 sional scientist, not of the Arts student; the instructor is only too 

 happy if he succeeds in imparting the information or establishing a 

 principle. Analogies and expressions have been freely used, what- 

 ever may have been their source. The writer recalls the origin of 

 some of them; others have been obtained from casual reading and 

 their source forgotten by him. 



It has always been the ambition of the writer to so stimulate the 

 student that he acquires some interest in reading Science. The sug- 

 gested readings placed at the end of each chapter are some that 

 have been found useful in testing the interest, capacity, and achieve- 

 ment of the more alert and responsive students. The lists have been 

 made up from the readings that have been recommended to such 

 students as have stopped at this instructor's desk to inquire where 

 they might find further information and discussion on topics men- 

 tioned in the lectures; the assignments are quite frankly extensions, 

 not collateral materials. Hence they are diverse in character, some 

 old and some quite recent. They merely indicate that a wide choice 

 should be made available. At the end of the last chapter the sug- 



