In 1898 Hopkins made the decision to leave clinical medicine for academia. He moved to Cambridge to develop the chemistry side of Sir Michael Foster physiology department. During the early 1900s Hopkins made significant discoveries concerning the chemical nature and nutritional value of proteins and the biochemistry of muscle contraction. Together with Sydney Cole he discovered a new amino acid, tryptophan. A series of feeding experiments conducted with Edith Woodcock showed that tryptophan must be present in dietary protein for a physiologically complete diet. Studies on the chemistry of muscle contraction with Walter Fletcher showed that lactic acid accumulated when oxygen was absent, and was broken down when oxygen became available again.
Hopkins scientific reputation was growing. In 1905 he was made a Fellow of the Royal Society. He was increasingly invited to be a guest speaker at meetings, and he used these opportunities to declare his vision and ambitions for a discipline of biochemistry. His most famous address was made in 1913 to the British Association for the Advancement of Science (now the British Science Association). In this speech he described the cell as a highly differentiated system with simple molecules in dynamic equilibrium’ with each other, and stressed that the cell was accessible to the experimentalapproach.
Chemical Differentiation in Animal Species: a talk given by Hopkins to the Natural History Society at Emmanuel College (1903)
Students and fellows regularly met in Hopkins’ Emmanuel College room to present papers and discuss the many exciting new scientific ideas of the early 1900s. In this paper Hopkins hints at a coming together of Mendel’s newly discovered genetic ideas and a biochemical approach to understanding inheritance.
(On loan from Emmanuel College, Cambridge)
Royal Society Election Certificate (1905)
In addition to his pigment and urine physiology studies, Hopkins’ election recognized his work on the chemistry of proteins As part of this work he developed a highly efficient way of crystallizing albumin and other proteins.
Photograph of Hopkins taken at the time of his election to the Royal Society
The respiratory process in muscle; and the nature of muscular motion
Walter Fletcher and Hopkins were jointly invited to deliver the Royal Society’s prestigious Croonian lecture in 1915. As well as presenting their findings on lactic acid, it was an opportunity to review current knowledge on the biochemistry of muscle contraction. The lecture was published in the Society's journal Proceedings of the Royal Society B in 1917.
Invitation from Lord Moulton to the inaugural dinner of the Medical Research Committee (1913)
The Medical Research Committee (later Council) was founded in 1913 to co-ordinate the distribution of medical research funds under the terms of the 1911 National Insurance Act. Lord Moulton was the MRC’s first chairman. Hopkins was a founder member, along with Walter Fletcher, who in 1914 became the Committee’s first secretary.
(On loan from the University Library, Cambridge)