Evans applied his energies to anatomical research under Franklin P. Mall. His studies of the vascular supply of the parathyroid gland led to a paper published with the famed surgeon William A. Halsted. Evans was credited with solving the problem of tetany following thyroid surgery. Evans pursued, with Charles Bardeen, the development of the vascular and lymphatic system; this work culminated in the section in Keibel and Mall's classic Manual of Human Embryology. He was less inclined to pursue with interest the clinical courses at Johns Hopkins, particularly when they took time from his innovative activities injecting embryonic blood vessels. He graduated in 1908, declining an internship and any other clinical training. By the time he graduated, Evans had a remarkable seven papers to his credit, of which only two were co-authored.
He disappointed his father by immediately joining Mall's laboratory as a research anatomist. It was quite clear that Herbert Evans was not returning to take over his father's surgical practice. An early trip to Germany led to a study of dyes with chemist Werner Schulemann, one of which now called "Evans' Blue" proved useful in the measurement of blood volume. In 1913, Mall created the Department of Embryology with funds from the Carnegie Institution in Washington. Evans enjoyed joint appointments in Anatomy and with the Carnegie Department of Embryology at Johns Hopkins.
In 1915, Benjamin Ide Wheeler of the University of California offered Evans the Chair of the Department of Anatomy at Berkeley. Evans was thirty-three, he had twenty-seven published papers to his credit, and a solid national and international reputation as a brilliant researcher and erudite scholar. Pleased with the offer, and the chance to return home, Evans brought with him to Berkeley two of his colleagues at Johns Hopkins, Katherine J. Bishop and George W. Corner. They quickly established a youthful and dynamic Department of Anatomy and Anatomical Research at Berkeley. Evans did not believe in lecturing on gross anatomy which he characterized as a static science taught to future surgeons. His lectures on microscopic anatomy were dramatic events, staged mostly for the benefit of the four of five best students and for his faculty members. He often was caustic with those medical students who had limited interest in anatomical research. Evans believed in Mall's concept that self-education is the only form of lasting value, with the student learning the inductive method through personal investigation and research.
Jacques Loeb played an important part in Evans' views and development. It was Loeb's deliberately conceived biological experimentation which appealed to Evans. It was the application of these principles that made Evans a great investigator and built the widely admired school of Berkeley anatomists. Despite its seeming diversity, Evans research was consistently devoted to the study of the problems of reproduction. His systematic investigation of the reproductive cycle began following his return to Berkeley in 1916. With the aid of vital stains he studied the atretic follicle, recognizing the importance of developing a method of determining the progress of the ovarian cycle. The key was provided through Evans' association with Joseph Long, Professor of Zoology, who had advanced the detection of ovarian function in experimental animals by means of vaginal smears. The pursuit of the reproductive cycle in the rat, and other animals, led to the fractionation of the hypophysis, with the separation and purification of its six hormones. Evans' experimental production of growth changes with pituitary extracts dated from the 1920s. Cho H. Li's partial synthesis of growth hormone began in Evans' laboratory. Evans' and Bishop's study of diets adequate for the maintenance of pregnancy led to their discovery of vitamin E, which was initially called the anti-sterility vitamin. This work led to the first studies on the B complex, and the need for this vitamin in lactation, and to the role of Vitamin A in the reproductive mechanism, and to the first observations on the diabetogenic action of the anterior hypophysis in animals.
Evans was a devoted student of history of science and medicine-an interest that he credited to Osler's stimulus. He was instrumental in the formation of a unique course in the history of biology and assisted Dean Langley Porter and Professor Chauncey Leake in the formation of the Department of the History of Medicine at UCSF, the first in the United States.
Herbert McLean Evans died in 1971. He made a monumental contribution to the field of endocrinology through his studies of the physiology of reproduction. Many have remarked that the ultimate recognition of his achievements eluded him. Four of his lines of research and discovery were often mentioned as deserving of the Nobel Prize: (1) development of the vascular system, (2) elucidation of the estrous cycle in the rat, and the role of pituitary gonadotropin in reproduction, (3) discovery of growth hormone, and (4) discovery of and isolation of vitamin E. The first of these was entirely Evans' own work. The other three were collaborative efforts, but Evans' contribution to each was crucial.References:
Raacke, I.D. "The Die is Cast"-"I Am Going Home": The Appointment of Herbert McLean Evans as Head of Anatomy at Berkeley. Journal of the History of Biology, Vol. 9, No. 2 (Fall 1976), pp. 301-322.
Saunders, J. B.de C. M. " Herbert McLean Evans M.D., Sc.D. (1882-1971). An Appreciation," J. Anat. (1972), Vol. 111, No. 1, pp. 187-189.
See also Conversations with Dr. Leslie Latty Bennett: The Research Tradition at UCSF. (San Francisco: Regents of the University of CA, 1992) for a former student's perspective on Evans research and influence as a faculty member.