The cordial reception given to this little book by the medical profession, by educators, and especially by the young men of the country, have by their demands for the book necessitated the appearance of new editions in such rapid succession that no .far-reaching changes in the text have been possible even if they had been needed. Happily, no extensive changes have been required. In the second edition several corrections, typographical and verbal, were made and additions made to the appendix. To the third edition the chapter on Development was added. The fourth and fifth editions received verbal changes here and.
