Herbert McLean Evans

Herbert McLean Evans (September 23, 1882–March 6, 1971) was a U.S. anatomist and embryologist.

He was born in Modesto, California. In 1908, he obtained his medical degree from Johns Hopkins University, eventually becoming its associate professor of anatomy. Evans moved back to California in 1915 and was made professor of anatomy at the University of California, in Berkeley, California, and held that position until his death.

His medical research at Berkeley addressed problems relating to human nutrition, endocrinology, embryology, and histology. In 1918, his research into the number of human chromosomes led him to believe the number to be 48, when most people assumed the number to be much higher. It was only later discovered that the correct figure was 46. Evans had much greater success however with hormones extracted from the anterior lobe of the pituitary gland. He isolated Human Growth Hormone, which was essential for human growth and development. In 1922 along with Katharine Scott Bishop, during feeding experiments on rats, he co-discovered Vitamin E which is needed for human reproduction. [cite journal
author = Evans H. M., Bishop K. S.
title = On the existence of a hitherto unrecognized dietary factor essential for reproduction
journal = Science
year = 1922
volume = 56
issue = 1458
pages = 650–651
url = http://links.jstor.org/sici?sici=0036-8075%2819221208%293%3A56%3A1458%3C650%3AOTEOAH%3E2.0.CO%3B2-Q| doi = 10.1126/science.56.1458.650
pmid = 17838496] Evans became director of the Institute of Experimental Biology at Berkeley, in 1931. He continued his research on vitamine E and was finally able to isolate the pure compound from wheat germs in 1937. He also determined the formula C₂₉H₅₀O₂. [cite journal
author = Evans H. M., Emerson O. H., Emerson G. A.
title = The isolation from wheat germ oil of an alcohol, a-tocopherol, having the properties of vitamin E
journal = Journal of Biological Chemistry
year = 1936
volume = 113
issue = 1
pages = 319–332
url = http://www.jbc.org/cgi/reprint/113/1/319] He was also instrumental in developing reproductive systems research with Miriam Sipson and C.H. Li, by studying the oestrus cycle of rats. Evans is also credited with developing Evans blue, a method which determines blood volume in humans and animals.

He died in Berkeley, California, aged 88.

Quotation

*"No single feature of man's past equals in importance his attempt to understand the forces of Nature and himself."

Bibliography

*Evans, H. McLean (1904) "A New Cestraciont Spine from the Lower Triassic of Idaho". The University Press: Berkeley, California.
*Evans, H. McLean and Scott, Katharine J. (1921) "On the Differential Reaction to Vital Dyes Exhibited by the Two Groups of Connective-tissue Cells". Carnegie Institution of Washington.
*Evans, H. McLean and Long, Joseph A. (1922) "The oestrous cycle in the rat and its associated phenomena". Univ. of California Press: Berkeley, California.
*Evans, H. McLean and Cole, Harold H. (1931) "An Introduction to the Study of the Oestrous Cycle in the Dog". University of California Press: Berkeley, California.
*Evans, H. McLean and Swezy, Olive (1931) "Ovogenesis and the Normal Follicular Cycle in Adult Mammalia". University of California Press: Berkeley, California.
*Evans, H. McLean and Becks, Hermann (1953) "Atlas of the Skeletal Development of the Rat (Long-Evans strain): normal and hypophysectomized". American Institute of Dental Medicine: San Francisco.
*Evans, H. McLean, ed. (1959) "Men and Moments in the History of Science". University of Washington Press: Seattle. ISBN 0-8371-2458-1

References