Because his father’s business required the family to move about (mostly through the West and Midwest), young McClung’s schooling was sporadic. By the time he was ready to enter high school, however, the family had settled in Columbus, Kansas (in the mid-1880’s) and McClung’s intellectual abilities began to show. He became especially interested in science; from his father he learned surveying, and from working in an uncle’s drug store, he learned pharmacy. Following this latter interest, he entered the University of Kansas School of Pharmacy in Lawrence in 1890, and completed the pharmacy course in two years, receiving his Ph.D. in 1892.
Gallery of Clarence McClung
Strong Hall, 1450 Jayhawk Blvd #200, Lawrence, KS 66045, United States
In the fall of 1893 McClung enrolled in the College of Liberal Arts. As an undergraduate his interests shifted from chemistry to zoology, particularly through the influence of S. W. Williston, who encouraged McClung’s natural mechanical bent and allowed him to work in the histology laboratory learning special techniques. Williston also entrusted McClung with teaching part of his course in histology during one semester. McClung received his Bachelor of Arts in 1896, and immediately entered graduate school at Kansas, receiving his Master of Arts in 1898, and Ph.D. in 1902.
Because his father’s business required the family to move about (mostly through the West and Midwest), young McClung’s schooling was sporadic. By the time he was ready to enter high school, however, the family had settled in Columbus, Kansas (in the mid-1880’s) and McClung’s intellectual abilities began to show. He became especially interested in science; from his father he learned surveying, and from working in an uncle’s drug store, he learned pharmacy. Following this latter interest, he entered the University of Kansas School of Pharmacy in Lawrence in 1890, and completed the pharmacy course in two years, receiving his Ph.D. in 1892.
Strong Hall, 1450 Jayhawk Blvd #200, Lawrence, KS 66045, United States
In the fall of 1893 McClung enrolled in the College of Liberal Arts. As an undergraduate his interests shifted from chemistry to zoology, particularly through the influence of S. W. Williston, who encouraged McClung’s natural mechanical bent and allowed him to work in the histology laboratory learning special techniques. Williston also entrusted McClung with teaching part of his course in histology during one semester. McClung received his Bachelor of Arts in 1896, and immediately entered graduate school at Kansas, receiving his Master of Arts in 1898, and Ph.D. in 1902.
Clarence Erwin McClung was an American zoologist and prairie pioneer cytologist. His study of the mechanisms of heredity led to his 1901 hypothesis that an extra, or accessory, chromosome was the determiner of sex.
Background
Ethnicity:
Of Scotch-Irish descent, McClung’s ancestors had come to the United States in 1740 and settled in Lancaster County, Pennsylvania.
McClung was born on April 5, 1870, in Clayton, California. His father, Charles Livingston McClung, was a civil and mining engineer, and his mother, Annie H. Mackey, the daughter of a physician.
Education
Because his father’s business required the family to move about (mostly through the West and Midwest), young McClung’s schooling was sporadic. By the time he was ready to enter high school, however, the family had settled in Columbus, Kansas (in the mid-1880’s) and McClung’s intellectual abilities began to show. He became especially interested in science; from his father he learned surveying, and from working in an uncle’s drug store, he learned pharmacy. Following this latter interest, he entered the University of Kansas School of Pharmacy in Lawrence in 1890, and completed the pharmacy course in two years, receiving his Ph.D. in 1892.
In the fall of 1893, McClung enrolled in the College of Liberal Arts. As an undergraduate, his interests shifted from chemistry to zoology, particularly through the influence of S. W. Williston, who encouraged McClung’s natural mechanical bent and allowed him to work in the histology laboratory learning special techniques. Williston also entrusted McClung with teaching part of his course in histology for one semester. McClung received his Bachelor of Arts in 1896, and immediately entered graduate school at Kansas, receiving his Master of Arts in 1898, and Ph.D. in 1902. During his graduate years, he spent one semester at Columbia University with the cytologist Edmund Beecher Wilson, and one summer (1898) working with William Morton Wheeler at the University of Chicago. Both of these men were interested in the nature and behavior of chromosomes, and it was through their influence that McClung’s attention was directed to these nuclear elements.
While still a graduate student at Kansas, McClung was appointed assistant professor of zoology, and later of histology and animal morphology from 1898 to 1900; in 1901 he was made associate professor of zoology and head of the zoology department. He served as curator of the university’s paleontological collections from 1902 to 1912, and was acting dean of the Medical School from 1902 until 1906. In 1906 he became professor of zoology, a post he held until 1912 when he accepted a call to become head of the zoological laboratories at the University of Pennsylvania, where he remained until his retirement in 1940. During the academic year 1940-1941 he served as acting chairman of the department of zoology at the University of Illinois, and in 1943-1944 was acting chairman of the biology department at Swarthmore College. Always interested in teaching, McClung introduced a variety of pedagogical innovations during his career. At Kansas, where he taught introductory biology, he deemphasized memorization and encouraged students to think through problems on their own. And at Pennsylvania, he served on many university committees concerned with curriculum reform and matters of basic educational policy.
McClung’s biological work covers several distinct areas of interest: paleontology, on which he wrote some early papers in 1895, 1905, and 1908, technical microscopy and microscopy techniques, and studies on chromosomes. The latter area includes his most important contributions.
Besides his teaching and research, McClung served in a number of administrative posts outside the university. In 1913 he was appointed a trustee of the Marine Biological Laboratories, Woods Hole, Massachusetts - he had taught part of the embryology course there in the summer of 1903 - and in 1914 a member of the investigative staff. In 1917 he became chairman of the Zoology Committee of the Division of Biology and Medicine of the National Research Council (NRC), and in 1919 the first chairman of its newly created Division of Biology and Agriculture (NRC). In the latter post, he initiated plans for a comprehensive biological abstracting service, which eventually led to the publication of Biological Abstracts, published by the Union of American Biological Societies, of which McClung became president of the board of trustees, 1925-1933. As chairman of the Division of Biology and Agriculture, he also initiated plans for standardizing biological stains, eventually giving rise to the Biological Stain Commission. He served as the managing editor of the Journal of Morphology from 1920 until 1946, and the associate editor of Cytologia from 1930 onward.
In addition, he received many honors, including membership in several honorary societies. The latter include Sigma Xi (national president, 1917-1921), Beta Beta Beta (president, 1936), and the National Academy of Sciences (1920). He was also the United States representative at the International Biological Congress in Montevideo, Uruguay, in 1930, a goodwill scientific ambassador (sponsored by the Rockefeller Foundation) to Japan (1933-1934), a recipient of the Distinguished Service Citation from the University of Kansas (1941), and a D.Sc. from Franklin and Marshall College (1942).
Achievements
Views
Like many biologists at the time, McCIung saw heredity and development as inextricably linked. Heredity operates, he maintained, by controlling the cell’s metabolic functioning. And since that functioning depends upon environmental circumstances (for the availability of raw materials, for example), it was clear that an individual’s ontogeny was molded by hereditary potentialities interacting with specific environmental conditions. This was a consciously epigenetic view, conditioned in part by reaction to the prevalence of particulate theories of heredity in the past (such as those of Haeckel or Weismann) which placed all emphasis on heredity. To McClung, the most important arena in which further understanding of the relationships between heredity and development could be worked out was cytology.
McClung’s work, and subsequently that of Wilson and Stevens, substantiated the concept of the individuality of the chromosomes. By associating the inheritance of one set of traits (sexual) with one particular chromosomal element, the McClung theory suggested that each chromosome was different from the others, governing one specific set of characteristics. At just about the same time, the concept of chromosomal individuality received considerable support from other quarters: particularly from the work of Boveri with polyspermy in the sea urchin, and that of T. H. Montgomery and W. S. Sutton.
Membership
American Morphological Society
,
United States
1901
American Association for the Advancement of Science
,
United States
1908
American Society of Zoologists
,
United States
1905
American Philosophical Society
,
United States
1913
American Society of Naturalists
,
United States
1927
Philadelphia Academy of Sciences
,
United States
1914
Wistar Institute of Anatomy and Biology
,
United States
1914
American Association of Anatomists
,
United States
1914
Washington Academy of Sciences
,
United States
1920
Personality
McClung was known as a congenial and friendly person by both his colleagues and students. Noted as a sensitive and meticulous worker, McClung was described by one student as "an artist in everything he does."
Interests
McClung had a broad range of interests involving athletics, English literature, music, photography, and dramatics.
Connections
McClung married Anna Adelia Drake of Lawrence, Kansas, on 31 August 1899; they had two children, Ruth Cromwell, and Della Elizabeth.