Clement C. Clay was born in Birmingham, Alabama in 1905. He graduated from Columbia University in 1927 and from McGill's Faculty of Medicine in 1932. During World War II, he served as a Lieutenant and later Commander in the medical corps of the United States Naval Reserve. In 1941, he was put on active duty and in 1942 worked at a U. S. Naval Hospital in Pensacola, Florida. In 1943 and 1944, he was sent by the Surgeon General to North Africa, Italy, and England on a special mission to study the handling of casualties and gather other information on military medical service in these countries. In 1944 he was able to study infection control measures during an outbreak of typhus in Naples. He retired from the Navy in 1946. He worked as a hospital administrator and Professor of Hospital Administration at the Columbia University School of Public Health from 1954 to 1970. He died in 1978.

Samuel Clay was born in London, England, and received his B.C.L. from McGill in 1898. He practiced as an advocate in Montréal and served the university as Acting Secretary and Bursar from 1904 to 1906. He later became a professor at the University of Cairo, Egypt, where he died in 1917.

Edward Waller Claypole was born on June 1, 1835, in Ross, Herefordshire, England.

He was a British American geologist and paleobotanist. He studied at the University of London, where he received the degrees of A.B. in 1862, S.B. in 1864, and Sc.D. in 1888. He moved to the United States in 1872 and served as Professor of Natural Sciences in Antioch College, at Yellow Springs, Ohio (1873-1881). For two years he was a paleontologist to the Pennsylvania Geological Survey. From 1883 to 1898 he was Professor of Natural Sciences in Buchtel College at Akron, Ohio. Because of the failing health of his wife, he resigned from this position and sought a southwestern climate. During the last three years of his life, he was a Professor of Geology and Biology at Throop Polytechnic Institute at Pasadena. California. He is the author of "The Lake Age in Ohio or, Some Episodes During the Retreat of the North American Ice-Sheet" (1887).

In 1865, he married Jane Trotter (1837–1870). In 1879, he remarried Catherine Benedicta Trotter (1846–1901). He died on August 19, 1901, in Pasadena, Los Angeles, California.

David Cleghorn was the husband of Jessie Mercer, and the father of Louisa Dawson Cleghorn.

J.D. Cleghorn was the Secretary of the Redpath Museum beginning in 1938.

Louisa Dawson Cleghorn was the daughter of John Cleghorn and Jessie Mercer.

Born in Cambridge, Massachusetts, in 1904 and educated at the University of Toronto (M.D. 1928) and Aberdeen University (D.Sc. 1932), Robert A. Cleghorn began his career as a junior intern at Toronto General Hospital in 1928. In 1946, he became Assistant Professor of psychiatry at the Allan Memorial Institute, in Montréal. From 1949 to 1960, he was Associate Professor of psychiatry at McGill and, from 1964 to 1970, was Professor of psychiatry and chairman of the department. Cleghorn succeeded Dr. D. Ewen Cameron as director of the Allan Memorial in 1964.