NICHOLAS, JOHN SPANGLER

(b. Allegheny, Pennsylvania, 10 March 1895; d. New Haven, Connecticut, 11 September 1963)

biology.

Nicholas was a descendant of two old Pennsylvania families. His father, Samuel Trauger Nicholas, was a Lutheran minister; his mother, formerly Elizabeth Spangler, had been trained as a teacher before her marriage. An only child, Nicholas was educated at Pennsylvania (now Gettysburg) College (B.S., 1916; M.S., 1917). He entered Yale as a graduate student in the autumn of 1917 but in 1918 interrupted his work there to enlist in the Army Medical Corps. Nicholas was assigned to the vaccine department of the Army Medical School in Washington, D.C., where he worked on methods of improving typhoid vaccine until his discharge in 1919. He then returned to Yale, where he received a Ph.D. in zoology in 1921. In the same year he married Helen Benton Brown.

After teaching for six years in the department of anatomy at the University of Pittsburgh, Nicholas returned to Yale in 1926 to teach zoology and remained there until his retirement in 1963. He became Sterling professor of zoology in 1939 and was chairman of the department of zoology from 1946 to 1956 and Master of Trumbull College from 1945 until his retirement. Nicholas performed many other administrative duties, at Yale and elsewhere. He served as editor of a number of biological journals, most notably the Journal of Experimental Zoology. He held office in a number of professional societies, including the American Philosophical Society and the National Academy of Sciences. As adviser to government agencies he was particularly influential as a consultant to the National Research Council on the effective use of scientific manpower during World War II.

Nicholas’ primary interest, however, was in embryology; and within this area his activities were quite varied. He studied experimentally the development of fishes, amphibians, and mammals; worked in endocrinology, reproductive physiology, and neurology; and conducted original and pioneering investigations so numerous and diverse that only the most important will be mentioned here.

Nicholas began his experimental work by studying various aspects of the development of asymmetry in the amphibian limb. Ross Harrison had previously shown, through grafting experiments on salamander larvae, that whether a limb will become a left or a right limb depends on the orientation of the limb bud with respect to its surroundings in the embryo at certain specified periods in development. That is, by rotating only a narrow ring of tissue surrounding the limb bud, Nicholas demonstrated that this ring contains the factors that interact with the limb bud to determine its asymmetry. Nicholas also performed experiments on amphibian embryos and larvae to elucidate the development of the nervous system. His vital staining experiments on amphibian eggs showed that extensive movements take place in the endoderm before gastrulation; previously it had been believed that such movements begin only at gastrulation.

Nicholas made an important contribution to the study of teleost development by being the first to improvise a method for removing the horny covering of the egg, thereby making it possible to apply the modern methods of experimental embryology to the eggs of these fishes. He also applied the new methods of experimental embryology to the study of mammalian eggs—this was his most important scientific contribution. Although not the first to attempt mammalian experimental embryology, Nicholas was the first to carry out an intensive program in this field. He studied young rat eggs, or young rat embryos or their parts, both in tissue culture and in grafts implanted at a number of sites in adult rats—and even on the chick chorioallantois. His most noteworthy experiments along this line demonstrated that single blastomeres, isolated at the two-cell stage and then transplanted into the uterus of foster mothers, could develop to the egg cylinder stage. This was the first experiment to demonstrate the flexible nature of mammalian development and to prove that the important embryological principles of induction and progressive differentiation are applicable to higher as well as to lower vertebrates.

BIBLIOGRAPHY

The most detailed biography of Nicholas, with a complete bibliography of his articles, is Jane M. Oppenheimer, “John Spangler Nicholas 1895–1963,” in Biographical Memoirs. National Academy of Sciences, 40 (1969), 239–289.

Nicholas’ professional correspondence is in the Archives Collection of the Sterling Library, Yale University.

Jane Oppenheimer