Герберт Маклин Эванс: Американдық анатомия және эмбриолог ғалымы

American anatomist and embryologist

Herbert McLean Evans (September 23, 1882 – March 6, 1971) was an American anatomist and embryologist best known for co discovering Vitamin E.

He was born in Modesto, California. In 1908, he obtained his medical degree from Johns Hopkins University.

Evans became associate professor of anatomy at Johns Hopkins University. Evans moved back to California in 1915 and was made professor of anatomy at the University of California, Berkeley, 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 is 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. Evans became director of the Institute of Experimental Biology at Berkeley in 1931. With Gladys Anderson Emerson, he reported the isolation of the pure Vitamin E from wheat germ in 1937. He also determined the formula C29H50O2. Evans was also instrumental in developing reproductive systems research with Miriam Elizabeth Simpson and Choh Hao 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. Evans took a strong interest in the history of science and was an active collector of rare books in the field. His collection was later acquired by the Harry Ransom Center at the University of Texas at Austin. He died in Berkeley, California, aged 88.

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