Lafayette Benedict Mendel was born on February 5, 1872 in Delhi, New York. His father, Benedict Mendel, was born in Aufhausen, Germany, in 1833, and emigrated to the United States in 1851; his mother, Pauline Ullman, was born in Eschenau in 1844 and arrived in the United States in 1870. They were married that same year. Two sons were born to them, the younger dying in 1901.
As a youth, Lafayette Mendel was unusually precocious, showing a fondness for study so marked that at the early age of fourteen he took the preliminary examinations for Yale in Greek, Latin, and mathematics, his training having been at the local school in Delhi. The following year he took the final examinations and entered Yale College in 1887, the youngest member in his class. As an undergraduate he gained a high record for scholarship, with Phi Beta Kappa standing, his studies being largely in the classics, economics, and the humanities in general, with but limited attention to the sciences. After graduating with the degree of A. B. in 1891, he entered the Sheffield Scientific School to begin the study of physiological chemistry with some thought of eventually studying medicine, but as he progressed, his interest became so great and his success so marked that he decided to make physiological chemistry his life work.
Mendel's decision to make physiological chemistry his main work proved a wise one for he was possessed of all the qualities that go to make a successful teacher, pleasing personality, sound judgment, and wide knowledge. Furthermore, he was demonstrating each year a striking ability to carry forward scientific research in this field of study. His intellectual honesty and keenness of vision contributed to his ultimate success. After receiving the degree of Ph. D. in 1893, he was appointed assistant in the Sheffield laboratory of physiological chemistry, thus beginning a teaching career of forty-two years at Yale. In the college year 1895-96 he was given leave of absence in order to carry on research with Professor Heidenhain at Breslau and with Professor Bauman at Freiburg, both eminent physiologists. In 1897 he was advanced to the rank of assistant professor in the Sheffield Scientific School, and in 1903 he was made professor of physiological chemistry with membership on the governing board of the Sheffield Scientific School. In 1921 he was appointed Sterling Professor of Physiological Chemistry in the university, with membership in the faculties of the graduate and medical schools and the Sheffield Scientific School. He died of a heart ailment after a long illness, his wife having predeceased him by only a few weeks.
Mendel is known for his work in nutrition, including the study of Vitamin A, Vitamin B, lysine and tryptophan. In conjunction with Thomas B. Osborne, Mendel was one of the first in America to recognize the existence of these accessory food substances so essential to health. Mendel belongs the credit of the pioneer work in America in the study of vitamins, more than twenty distinct publications of the results of their experimental work appearing in the scientific journals during a period of fifteen years. He was one of the directors of the Russell Sage Institute for Pathology, a member of the council on pharmacy and chemistry of the American Medical Association, research associate of the Carnegie Institution of Washington, member of the educational advisory board of the John Simon Guggenheim Medical Foundation, first president of the American Institute of Nutrition, and a member of the editorial board of the Journal of Biological Chemistry. Many honors came to him in recognition of his accomplishments in his chosen field of work. In 1913 he was made a member of the National Academy of Sciences. In 1927 the gold medal of the American Institute of Chemists was given him "for his outstanding contributions to chemistry, " and in 1935 the Chemist's Club of New York gave him the Conné Medal "for his outstanding chemical contributions to medicine. "
(This book was originally published prior to 1923, and rep...)
(This book was originally published prior to 1923, and rep...)
(This book was digitized and reprinted from the collection...)
(This is a pre-1923 historical reproduction that was curat...)
Mendel's position in the world of science rests mainly upon his accomplishments in the field of nutrition, for through careful experimental work he blazed a trail that led to many new conceptions. His work, for example, on the relationship between the chemical constitution of food proteins and their biological value in nutrition, and the influence on the nutritional processes of hitherto unknown substances, the vitamins, and their relation to health and disease was of epochmaking character. In conformity with other observers, notably Sir Frederick Gowland Hopkins, Osborne and Mendel found (1910) that normal strength and vigor could not be maintained on a dietary made up of purified food products no matter how large in amount or varied in character. From their experiments on rats it was soon found that milk contained a watersoluble substance, now known as vitamin B, and butter fat, a substance soluble in fat now known as vitamin A, both essential for maintenance and growth. They showed that the absence of vitamin A in the food led to a characteristic eye disease, xerophthalmia, which could not be cured by any ordinary means but was quickly remedied by a drop or two of cod-liver oil each day or by a few milligrams of an extract of green leaves, which supplied the needed vitamin. In one of their early papers they stated, "The researches which have been devoted in recent years to certain diseases, notably beri-beri, have made it more than probable that there are conditions of nutrition during which essential, but, as yet, unknown substances must be supplied in the diet if nutritive disaster is to be avoided". It soon became apparent that growth-promoting properties were associated with many and widely divergent tissues and fluids, thus implying a fairly broad distribution of these accessory substances.
Equally far-reaching was his work together with Osborn on the nutritive value of the different food proteins, qualitative and quantitative differences in the content of amino acids in proteins having suggested possible differences in biological value. By long series of feeding experiments, they found that proteins in which there is a shortage or a complete absence of certain amino acids are incapable of maintaining growth. Proteins could thus be divided into complete and incomplete proteins, those of good or poor biological quality. As a result of their experimental work, much valuable information was gained on the relative nutritive value of a great variety of food proteins, such for example as the proteins of wheat, rye, oats, and barley. In these and other ways Mendel helped to revolutionize the existing theories of nutrition.
a member of the National Academy of Sciences
On July 29, 1917, Mendel was married to Alice R. Friend; they had no children.
