ACKNOWLEDGMENTS 



MOST of the drawings for this book were made by 

 students in my classes at the Normal School. Two of 

 the plates were kindly furnished by the Educational 

 Review, one by Ginn & Company, and several by The 

 Macmillan Company. Due credit is given under each 

 figure. 



A number of physicians, superintendents, principals, 

 and teachers of physiology read parts or all of the 

 manuscript, and I am greatly indebted to them for 

 many helpful suggestions and criticisms. 



I am also indebted to Professor W. S. Watson, of the 

 State Normal School, Whitewater, Wisconsin, to Pro- 

 fessor C. E. Patzer, of Milwaukee, and to Mr. Lewis 

 C. Sleeper, of Milwaukee, for rendering valuable assist- 

 ance in the proof reading; and to Miss Delia G. Ovitz, 

 Librarian, State Normal School, Milwaukee, for pre- 

 paring the .index. 



JOHN I. JEGI. 



STATE NORMAL SCHOOL, MILWAUKEE, 

 June, 1903. 



