One of the most enduring monuments to Dr. Pepper's zeal and generosity is the Free Library of Philadelphia. In 1889 his uncle, George S. Pepper, bequeathed the sum of one hundred and fifty thousand dollars "to the trustees of such Free Library which may be established in the city of Philadelphia." From the beginning Dr. Pepper took a warm interest in the Free Library movement. It was under his leadership that the library was organized, and he was made the first president of its board of trustees. Speaking of his activity in this direction, the librarian, Mr. John Thomson, said: "No detail was too small for his personal attention. No plan for its future growth was too large for his ambitious hope of both public and private support. The remarkable and rapid increase in the circulation of the Free Library, the multiplication of its branches, the organization of all its departments on a broad and generous plan, his success in enlisting a large number of able fellow-workers, his clear, plain statements to Councils and the city authorities, his activity in securing needed legislation at Harrisburg, were some of the results of that intelligent energy which enabled him to do so much and to do it so well." The bequest of the Pepper family has been supplemented by ample appropriations by the City Councils, and the Free Library is now one of the most important institutions in Philadelphia. The library at present has twelve flourishing branches, while the combined circulation of the system for the year 1898 was 1,738,950 volumes. Dr. Pepper was also connected with many scientific bodies. He was Vice-President of the American Philosophical Society, and President of the first Pan-American Medical Congress in 1893. He was a Fellow of the College of Physicians; President of the Philadelphia Pathological Society from 1873 to 1876; Director of the Biological Section, Academy of Natural Sciences; President, in 1886, of the American Climatological Association; President of the Foulke and Long Institute for Orphan Girls; President of the First Sanitary Convention of Pennsylvania; and in 1882 he was a member of the Assay Commission of the United States Mint. He received the degree of LL. D. from Lafayette College in 1881, and from the University of Pennsylvania in 1893.