Two years later he removed to Buffalo, where he practiced five years, and wrote and published a number of papers on the causes and treatment of cholera, which ravaged that city in 1849 and 1851. Dr. Lewis during those years of practice became impressed with the necessity of physical culture to prevent disease, and in 1855 he gave up the practice of his profession, and began a course of lecturing and writing on the subject of public and personal hygiene. During four years he lectured almost every night, giving his days to the invention of his new system of gymnastics.

In 18(j0, having j)erfected this system, he abandoned the platform and settled in Boston, where he established his normal school for physical training. He was assisted in teaching by the celebrated Dr. Walter Channing, Dr. Thomas Hoskins and other well-known medical scholars, and within seven years more than four hundred persons had been graduated from his normal school, and were spreading the principles of his system of physical training throughout the land. He next established a seminary for girls in Lexington, Mass., his object being to illustrate the possibilities in the physical development of girls'during their school-life. This seminary rapidly became popular, and attracted pupils from all parts of the country and even from Central America and the West Indies. Dr. Lewis remained in Boston until 1882, when he removed to Yonkers and established a magazine in Xew York devoted to sanitary and social science, and known as IHo Lewis' Monthbj.