Given to many audiences of boys in High-School, Academy, Y.M.C.A. and Summer Camp. The Institute and Training School of Young Men's Christian Associations, Chicago and Lake Geneva. October 7, 1908. Dr. Winfield S. Hall, Northwestern Medical School, Chicago, Ill. My Dear Dr. Hall: I want to express my appreciation of your talk to boys on Sexual Hygiene. I listened with the greatest of interest to your presentation before the Boys' Conference at Lake Geneva the past summer and it seemed to me that both in substance and in form of presentation you hit the nail on the head in a way I had never before seen it done. I believe that your contribution to boys in this direction is to be even greater than that which you have been making to young men. Sincerely yours, FRANK H. BURT, President. State Agricultural College of Colorado. Dr. Winfield S. Hall, Fort Collins, Colo., October 27, 1908. Northwestern University Medical School, Chicago. Dear Doctor: I wish to testify to the value of your lecture to boys from 12 to 16 years of age. You have touched a vital subject in a most original way that impresses every boy that hears you. You lead up to your "Secret of Manhood" in a manner that holds the attention, impresses the truth you want to teach, so that it is sure to be of lasting good. This lecture I regard as the very best of its kind, which I have ever heard. Sincerely yours, W.H. OLIN. Vice Dean, State Agricultural College of Colorado. Princeton Township High School. Princeton, Ill., October 6, 1908. Dr. Winfield S. Hall of the Northwestern University Medical School recently gave a talk to our high school boys along physiological lines, setting forth very scientifically but plainly many delicate and important truths which every boy should know. Dr. Hall is a master of his subject and his manner is so dignified and yet sympathetic that he commands respect and holds the closest attention. I feel sure that such a talk given to boys and young men does a great amount of good. Sincerely, H.S. MAGILL, JR., Principal. International Committee, Young Men's Christian Association. W.S. Hall, M.D., Chicago, Ill. Chicago, Ill., October 4, 1908. My dear Doctor: