This collection contains correspondence (approximately 150 letters), subject files, and notes on various research projects. The various subject areas include the central nervous systems, brains, and physiologies of many animals. Included are some anatomical drawings.

Includes correspondence, autobiographical notes, addresses, articles, and drawings. The collection reflects Riddle's interests in breeding, heredity, and evolution. He was interested in humanism and the presentation of biological and evolutionary theories. There is much information on Riddle's activities in favor of freedom of scientific teaching, especially in high schools.

In addition to extensive correspondence, there are numerous laboratory notes, lecture notes, drafts of published papers, reports. This material documents Long's career, with much on his work with diabetes, including the International Diabetes Federation. His 1950 trip to Japan as an advisor to Japanese medical schools on medical education is also documented. In addition, there is substantial material on the Yale University Department of Physiology and the School of Medicine.