Copyright, 1915, by W. B. Saunders Company. Reprinted August, 1915. Revised, entirely reset. 



reprinted, and recopyrighted October, 1917. Reprinted July, 1918. Revised, 



.entirely reset, reprinted, and recopyrighted August, 1920 . 



Copyright, 1920, by W. B. Saunders Company 



Reprinted February, 1921 



Reprinted January, 1922 



MADE IN U. S. A 



