I have been at all times greatly assisted by the advice 

 of Dr. C. M. Jackson, under whose direction the work was 

 commenced and who has untiringly aided until its comple- 

 tion. 



I am also under obligations to Dr. A. C. Eyclesheimer, 

 of St. Louis University, Dr. D. D. Lewis, of the University 

 of Chicago, and to Dr. L. F. Barker, of the Johns Hopkins 

 University , for many helpful suggestions and encourage- 

 ment. 



I am greatly indebted to Mr. Roy Dimmitt, superin- 

 tendent of Manual Arts, Birmingham Public Schools, Bir- 

 mingham, Alabama, for lettering the plates; and to Mr. 

 Alfred Streedain, artist to the department of Anatomy, St. 

 Louis University, for lettering the projections. 



