Sheridan Lea wrote the section on physiological chemistry in Foster's Textbook of Physiology and as University Lecturer on physiology from 1883 to 1896 dealt with that subject; this was carried on by A. Eichholz of Emmanuel College until a University lectureship in chemical physiology was established by Grace of June 12, 1898, and filled by the appointment of Frederick Gowland Hopkins, who in 1902 became Reader in that subject. In 1910 Trinity College added to this appointment a Praelectorship and a fellowship, and in 1914 the University elected him to the newly established professorship of biochemistry, tenable with the Readership and Praelectorship, but without any additional stipend. The Sir William Dunn Professorship of Biochemistry was established by Grace of February 12, 1921, and the previous chair of biochemistry was suppressed. This was endowed with £25,000 out of £165,000 conveyed to the University by the Trustees of the late Sir William Dunn.

The Department of Biochemistry was separately constituted in 1914; from 1908 the teaching was carried on in part of the old physiological laboratory, and after this was vacated by Professor Langley, the whole of the available accommodation was used for biochemistry and from 1919 to 1924 additional space was provided in the Balfour Laboratories in Downing Place. The Dunn Trustees' benefaction erected and maintained the new department in Tennis Court Road, which was opened on May 9, 1924, by Lord Balfour.

SIR George Downing (1684–1749), Bart., K.C.B., of Gamlingay, by his will dated December 20, 1717, left his property in Cambridgeshire, Bedfordshire, and Suffolk to trustees who in default of certain issue were directed to found Downing's (sic) College. His cousin Sir Jacob Garret (or Garrard) Downing, on whom the estates devolved, died without issue in 1764, and after more than thirty years' litigation the foundation of the college was recommended by the Privy Council on September 22, 1800. The college charter provided for two professorships—one of the Laws of England and the other of Medicine—as part of the college; these were filled up some years before the foundation stone of the college was laid on May 18, 1807.

On February 27, 1882, a Statute approved by the Queen in Council provided that the professor should receive from the University £300 more annually than the amount received as a fellow from Downing College, but not including his lodge in the college or any equivalent for it. Under the Statutes promulgated by the Royal Commission dated 1925 Downing College was relieved of any financial responsibility for future Downing Professors. The 1926 Statutes of Downing provide that, when the finances of the college permit, a Downing Reader in Medicine shall be appointed for three years by the Governing Body. The Downing Professorship of Medicine was abolished after the death of J. B. Bradbury (1841–1930), who held the chair for thirty-six years.