Oscar Riddle papers, 1919-1963


Date: 1919-1963 | Size: 3.5 Linear feet, Ca. 3500 items


Includes correspondence, autobiographical notes, addresses, articles, and drawings. The collection reflects Riddle's interests in breeding, heredity, and evolution. He was interested in humanism and the presentation of biological and evolutionary theories. There is much information on Riddle's activities in favor of freedom of scientific teaching, especially in high schools.

Background note

Oscar Riddle (1877-1968, APS 1926) was a zoologist and physiologist. He spent most of his professional career at the Station for Experimental Evolution at Cold Spring Harbor, Long Island. His research focused on birds and reproduction. Oscar Riddle was born in 1877 in Cincinnati, Indiana, near Bloomington, the son of Jonathan Riddle and Amanda Emeline Carmichael, farmers. His father died when Oscar was still a boy, and he helped to support his family by working on neighboring farms and trapping animals from a young age. In 1896 he enrolled at Indiana University to study biology but he stayed only until 1897 when he left to collect specimens for the U.S. Commission of Fisheries in Puerto Rico. There he worked as a science teacher in several schools, including the Model and Training School in San Juan and several teachers' institutes. In 1901 he traveled to Trinidad and the Orinoco River delta to collect fish specimens for his own use.

Later that year he returned to Indiana University which granted him his B.A. in 1902. Riddle subsequently enrolled in the University of Chicago's graduate program in zoology. He worked as a teaching assistant and, under the guidance of Charles O. Whitman, began experimenting with the evolution of color patterns in domestic fowl. Financial difficulties compelled him to interrupt his studies in 1903 to teach physiology at Central High School in St. Louis, Missouri. In 1906 he was able to resume his work at Chicago, and in 1907 he received his Ph.D. in zoology. Riddle continued to work at the University of Chicago for the next four years, first as an associate in zoology and embryology and a research assistant in experimental therapeutics and, after 1908, as an instructor. Riddle lost this position in 1911 as a result of a reorganization in the zoology department; however, Whitman retained him to care for his pigeon colony and help in the preparation of his voluminous papers for publication. The following year Riddle accepted an appointment as research associate at the Carnegie Institution of Washington, and in 1913 he moved to the Institution's Station for Experimental Evolution at Cold Spring Harbor on Long Island. Except for serving as a captain in the U.S. Army Sanitary Corps during World War I, Riddle remained at the station for the rest of his career.

At Cold Spring Harbor Riddle's research focused on organic development and heredity. He was especially interested in pigment distribution and sexual determination and reversal. He tended to study these phenomena in terms of biochemistry and physiology rather then Mendelian genetics. In this he was influenced by the work of his mentor Whitman. Riddle's three-volume compilation of Whitman's papers, essentially an anti-Mendelian approach to such problems as inheritance of feather patterns, sexual behavior, and reproductive activities, was published in 1914.

Riddle made one important scientific contribution was his discovery in 1932 of a hormone produced by the anterior pituitary gland, which stimulates mammaries to produce milk. Until then scientists had generally believed that lactation was triggered by either the placenta, the corpus luteum, or the ovaries. Riddle and his collaborators discovered that an extract of the pititare gland that had been shown by George W. Corner to induce lactation was a protein. They named it prolactin. Within the next five years Riddle was able to demonstrate that prolactin also induced production of milk in rats and crop milk in pigeons.

The discovery of prolactin remained Riddle's only significant contribution. Partly as a result of his overconfidence and dogmatism, most of the findings in Riddle's more than 200 research articles were superseded by the work of geneticists. Ironically, Riddle himself worked diligently to convince the public of the correctness of new scientific discoveries.

In addition to his scientific research, Riddle was also concerned with the ways in which biology was taught in American high schools. He was particularly critical of the failure to convey to high school students major advances in the life sciences because of what he called the "anti-science, anti-medical, anti-vivisection and anti-evolution crusades." Riddle explained his critical stance in an address he delivered in 1936 in St. Louis as vice president of the American Association for the Advancement of Science and chairman of its zoology section. The lecture, which was published in Science under the title "The Confusion of Tongues," created significant controversy. Six years later Riddle became the chairman of a committee created by the Union of American Biological Societies that substantiated his accusations that religious strictures were responsible for preventing exposure of many public school students to the theory of evolution. In addition, Riddle published numerous articles in which he encouraged teachers to stand up to religious dogmatism and make their students biologically literate. He was a founder of the National Association of Biology Teachers, and in the first article in the first issue of the organization's journal The American Biology Teacher (1938), Riddle urged teachers of the life sciences to "pull together" in order to prevent further weakening of their discipline.

Riddle was an active member of several professional associations. He served as president of the Association for the Study of Internal Secretions (1928-1929), vice president of the American Academy of Arts and Sciences (1935-1936), and president of the American Rationalist Federation (1959-1960). He chaired the American delegation to the Second International Congress for Sex Research in London, England (1930), and represented the Carnegie Institution at the Second Pan-American Congress of Endocrinology in Montevideo, Uruguay (1941). In addition, he was section editor of Biological Abstracts (1926-1946) and on the publication board of Endocrinology (1931-1934, 1939-1942). Among his awards and honors are the Gold Medal of the American Institute of the City of New York's (1934), the Humanist of the Year Award of the American Humanist Association (1958), and the Distinguished Service Award of the National Association of Biology Teachers (1958). He was elected to the American Academy of Arts and Sciences in 1934 and the National Academy of Sciences in 1939.

In 1937 Riddle married Leona Lewis; they had no children. In 1945 he retired to Plant City, Florida. He continued to study and write about biology until his death in 1968.

Digital objects note

This collection contains digital materials that are available in the APS Digital Library. Links to these materials are provided with context in the inventory of this finding aid. A general listing of digital objects may also be found here.

Collection Information

Physical description

Ca. 3500 items.


Presented by the Riddle estate and accessioned, 1969 (1969 615ms). Additional photocopied papers presented by George W. Corner and accessioned, 09/--/1972 (1972 1813ms).

Physiology, Biochemistry, and Biophysics Note

Scholars of physiology, biochemistry, or biophysics may find the following of interest:

Northrop, John Howard, 1891-1987Correspondence (2 items)1959-1961English

Indexing Terms

Corporate Name(s)

  • University of Chicago. -- Dept. of Zoology.


  • Sketches.

Personal Name(s)

  • Blakeslee, Albert Francis, 1874-1954
  • Dreiser, Theodore, 1871-1945
  • Huxley, Julian, 1887-1975
  • Kinsey, Alfred C. (Alfred Charles), 1894-1956
  • Moe, Henry Allen, 1894-1975
  • Riddle, Oscar, 1877-1968
  • Whitman, Charles Otis, 1842-1910


  • Biology.
  • Birds -- Research.
  • Breeding.
  • Evolution.
  • Genetics.
  • Heredity.
  • Physiology.
  • Pigeons.
  • Science -- Study and teaching (Secondary)
  • Zoology.

Detailed Inventory

 I. Correspondence
 Allen, Gordon
 American Academy of Arts and Sciences
 American Association for the Advancement of Science
 American Civil Liberties Union of Florida
 American Express Company
 American Humanist Association
 American Institute of Biological Sciences. Visiting Biologists Program
 American Institute of Biological Sciences. Visiting Biologists Program. Participating Colleges
 American Institute of the City of New York
 American Medical Association. Council on Pharmacy and Chemistry
 American Philosophical Society
 American Rationalist
 Anderson, Carl
 Anderson, Rudolph J. (Rudolph John), 1879-1961
 Animal Behavior
 Banaras Hindu University
 Banta, Arthur M. (Arthur Mangun), 1877-1946
 Barnum, William
 Bates, Robert W.
 Beach, Scott; Floyd, Oscar; McCoy, Robert; Poser, Ernest
 Beadle, George Wells, 1903-1989
 Beltran, Enrique, 1903-1994
 Benedict, Cornelia Golay, 1870-1961
 Benedict, Francis Gano, 1870-1957
 Benhre, Elinor H.
 Benitez-Flores, Manuel
 Blakeslee, Albert Francis, 1874-1954
 Breneman, W. R. (William Raymond), 1907-1992
 Bronk, Detlev W. (Detlev Wulf), 1897-1975
 Brooks, Chandler McC.
 Brother John
 Bruton, James D., 1908-1995
 Bulkley, Robert Johns, 1880-1965
 Burton, James D.
 Busch, Fred W.
 Canfield, Cass, 1897-1986
 Cardiff, Ira D. (Ira Detrich), 1873-1964
 Carnegie Institution of Washington
 Carnegie Institution of Washington. Office of Publications
 Carter, Mary Louise
 Castle, William E. (William Ernest), 1867-1962
 Caulfield, Gordon
 Chu, Jennings Pinkwei, b. 1895
 Cold Spring Harbor Laboratory
 Cole, Leon J. (Leon Jacob), 1877-1948
 Collier's (Magazine)
 Colligan, Francis James, 1908-1974
 Collins, LeRoy
 Collins, Nicholas E.
 Corner, George W. (George Washington), 1889-1981
 Cowdry, E. V. (Edmund Vincent), 1888-1975
 Crampton, C. Ward (Charles Ward), 1877-1964
 Crocker, William, 1876-1950
 Davenport, Charles Benedict, 1866-1944
 Davis, Watson, 1896-1967
 de Bodo, Richard C.
 Dombrowski, James A. (James Anderson), 1897-1983
 Domodaran, M.
 Dreiser, Theodore, 1871-1945
 Dunn, L. C. (Leslie Clarence), 1893-1974
 Eaton, Cyrus Stephen, 1883-1979
 Edwards, L. K.
 Encyclopedia of Sexual Behavior
 Endocrine Society
 Esquire, inc.
 Eugenics Quarterly
 Excerpta Medica
 Faber, Shepard M., 1928-2015
 Farisch, T. Adolph
 Fassett, F. G. (Frederick Gardiner), 1901-1991
 Fast Journal
 Fink, George
 Florida Council of Churches. Church and Higher Education Conference
 Florida State School Superintendent
 Forbes, Alexander
 France. Chambre des deputes
 Free Humanist
 Free Mind
 Freethinkers of Southern California
 Friendship Liberal League
 Fuller, Harry J., 1907-1973
 Gallant, Joseph
 Grobman, Arnold B. (Arnold Brams), 1918-2012
 Gulick, Addison, 1882-1969
 Hall, Thomas Steele, 1909-1990
 Harper's Magazine, Inc.
 Harrison, J. W.
 Haskins, Roy
 Hecht, Hugo
 Heiken, Herbert
 Hendrie, William E.
 Hill, Leslie
 Hollander, W. F. (Willard F.)
 Horizon Press
 Hoskins, R. G. (Roy Graham), 1880-1964
 Howard College
 Howard Junior High School
 Huxley, Julian, 1887-1975
 India. Embassy. (United States)
 Indian Science Conference
 Indian Science Congress
 Instituto Butantan
 Instituto de Fisiologia
 International Planned Parenthood Federation
 Jeffers, George W., 1897-1995
 Johnson, James Hervey
 Journal of the National Cancer Institute
 Kandel, I. L. (Isaac Leon), 1881-1965
 Kellogg, John Harvey, 1852-1943
 Kendeigh, S. Charles (Samuel Charles), 1904-1986
 Kessler, John J.
 King, Martin Luther, Jr., 1929-1968
 King, Willford Isbell, 1880-1962
 Kinsey, Alfred C. (Alfred Charles), 1894-1956
 Kinsley, Carl
 Kline, B. S. (Benjamin Schoenbrun), b. 1886
 Komai, Taku, b. 1886
 Kramer, Sol
 Krizenecky, Jaroslav, 1896-1964
 Larson, Martin A. (Martin Alfred), 1897-1994
 League of Nations. Commission on Biological Standardization
 LeFebvre, Eugene H.
 Lehrman, Daniel S., 1919-1972
 Leisanides, Theodophos
 Levi, Wendell Mitchell, 1891-1976
 Lewis, Joseph
 Library on Man's Place in Nature
 Lichtenwalter, Myrl Carl, 1908-1988
 Lightner, Jerry P., 1929-2010
 Lillie, Frank Rattray, 1870-1947
 Lyons, W. R.
 McAtee, W. L. (Waldo Lee), 1883-1962
 McCann, S. M. (Samuel McDonald), 1925-2007
 McCormick, Katharine Dexter, 1875-1967
 McDaniels, G. H.
 McGraw-Hill Book Company
 Martin, W. Edgar
 Mathews, Albert P., 1871-1957
 Miami Herald
 Miller, Robert R.
 Minoura, T.
 Moe, Henry Allen, 1894-1975
 Moore, Hugh, 1887-1972
 Morrow, Felix
 Moulton, Forest Ray, 1872-1952
 Muller, H. J. (Hermann Joseph), 1890-1967
 Mussio Fournier, J. C. (Juan Cesar), 1890-1961
 Muzzey, David Saville, 1870-1965
 Nance, Ellwood C. (Ellwood Cecil), 1900-1965
 National Academy of Sciences (U.S.)
 National Academy of Sciences (U.S.). Indian Science Congress
 National Association of Biology Teachers
 Nelson, Carl J.
 New York Times
 Northrop, John Howard, 1891-1987
 Osterhout, W. J. V. (Winthrop John Van Leuven), 1871-1964
 Perry, R. Barton (Ralph Barton), 1876-1957
 Peters, James Arthur, 1922-1972
 Phi Delta Theta Fraternity
 Philosophical Library
 Piel, Gerrard, 1915-2004
 Planned Parenthood Federation of America
 Popenoe, Paul, 1888-1979
 Population Reference Bureau
 Pottenger, Francis Marion, 1869-1961
 Protestants and Other Americans United for Separation of Church and State
 Puerto Rico. Department of Education
 Purohit, K. G.
 Rabinowitz, Louis M. (Louis Mayer), 1887-1957
 Radio Mundial S. A. (Lima, Peru)
 Ramaswami, L. S.
 Rauville, X. de
 Reed, Mildred B.
 Reimann, ------
 Reimann, Stanley P. (Stanley Philip), 1891-1968
 Reis, Jose
 Reprint Acknowledgments
 Richards, A. Glenn (Albert Glenn), 1909-1993
 Riddle, Leona Lewis, 1896-1968
 Riddle, Oscar, 1877-1968.
Confusion of Tongues (Correspondence)
 Riddle, Oscar, 1877-1968.
Endocrines and Constitution in Doves and Pigeons (Correspondence)
 Riddle, Oscar, 1877-1968.
Unleashing of Evolutionary Thought (Disposition)
 Riddle, Oscar, 1877-1968.
Unleashing of Evolutionary Thought (Reviews, Responses to Complimentary Copies, etc.)
 Robinson, Gerald G.
 Rockefeller Foundation
 Roosevelt, Franklin D. (Franklin Delano), 1882-1945
 Rose, Mason
 Rosenblueth, Arturo, 1900-1970
 Rowe, Allan Winter, 1879-1934
 Royal Society of Arts (Great Britain)
 Rusk, Dean, 1909-1994
 Samuels, Leo Tolstoy, 1899-1978
 Sargent, Porter Edward, 1872-1951
 Sarkar, B. B.
 Saturday Review
 Savarese, John J.
 Sax, Karl, 1892-1973
 Sayedud-Dix, M.
 Scroll (Phi Delta Theta)
 Scopes, John Thomas, 1900-1970
 Scott, Robert H.
 Seldes, George, 1890-1995
 Shake, Curtis G. (Curtis Grover), 1887-1978
 Simpson, M. E.
 Simpson, Robert
 Smathers, George A. (George Armistead), 1913-2007
 Smith, Warren Allen
 Smith, Winfield
 Sociedade Brasileira de Patologia Clínica
 Solberg, Archie Norman, 1909-1977
 Sweet, Donald H.
 Swift, Kenneth D.
 Syracuse University. Summer Science Conference
 Tampa Morning Tribune
 Taylor, Arthur L.
 Taylor, Ruby Shearer, 1930-2009
 Teas, Howard J. (Howard Jones), b. 1920
 Thapliyal, J. P.
 Thomas, Erica Eisner
 Thomas Paine Foundation
 Thompson, Jessie C.
 Toda, Kenji
 Truth Seeker Company
 Turner, Henry H., 1892-1970
 United States. Army
 United States. Department of Health, Education, and Welfare
 United States. Department of State
 United States. Department of State. Division of Cultural Cooperation
 United States. Foreign Service
 University Club of Chicago
 University of Chicago. Academic Appointments
 University of Chicago. Alumni Foundation
 Urey, Harold Clayton, 1893-1981
 Letter to Oscar Riddle, 1877-1968
1951 September 17 
 Van Tienhoven, Arius, 1886-1965
 Vetter, George B.
 Wall Street Journal (Firm)
 Whitman, Charles Otis, 1842-1910
 Wilson, Edwin H., 1898-1993
 Wirt, John L.
 Woodward, Robert Simpson, 1849-1924
 Woolf, Samuel
 Worden, Alastair N., 1916-1987
 World Population Emergency Campaign (U.S.)
 Zois, F.
 Zubiran, Salvador, 1898-1998
 -----, Gwin
 -----, Jerry
 -----, Manolo and Ana
 -----, Ted
 -----, Wiloslov
 II. Manuscripts
 Riddle, Oscar, 1877-1968.
Accion de la Prolactina Sobre
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
American Philosophical Society
1960 April 22 
 Riddle, Oscar, 1877-1968.
American Rationalist Federation Citation for Linus Pauling
 Riddle, Oscar, 1877-1968.
American Rationalist Federation, Presidential Address
 Riddle, Oscar, 1877-1968.
Among the Hormones
 Riddle, Oscar, 1877-1968.
Animal Hormones Affecting Growth...
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Autobiographical Notes
 Riddle, Oscar, 1877-1968.
Biography and Outside Activities
 Riddle, Oscar, 1877-1968.
Biological Sources of Human Behavior
 Riddle, Oscar, 1877-1968.
Biologist Speaking
 Riddle, Oscar, 1877-1968.
Biology becomes Social
 Riddle, Oscar, 1877-1968.
Biology in and not in the High School
 Riddle, Oscar, 1877-1968.
Biology Tomorrow
 Riddle, Oscar, 1877-1968.
Birds as Material for Elucidating the Processes of Animal Reproduction
 Riddle, Oscar, 1877-1968.
Birth Control and the Real Religious Issue in the Campaign
 Riddle, Oscar, 1877-1968.
Chemical Analysis of Streptopelia
 Riddle, Oscar, 1877-1968.
Church-State in the United States
 Riddle, Oscar, 1877-1968.
Complete Sex-Transformation in Adult Animals
 Riddle, Oscar, 1877-1968.
Confusion of Tongues (Press Releases)
 Riddle, Oscar, 1877-1968.
Contemplating the Hormones
 Riddle, Oscar, 1877-1968.
Control of Heredity
 Riddle, Oscar, 1877-1968.
Crucial Competition with Russia in Science Education
 Riddle, Oscar, 1877-1968.
Cyclic Changes in Blood Calcium, Phosphorus, and Fat in Relation to Egg Laying
 Riddle, Oscar, 1877-1968.
Developmental Disturbance and Transformation of a Hereditary Character: The Sex Character
 Riddle, Oscar, 1877-1968.
Differentiating Some Functions of the Anterior Pituitary Hormones
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Education for All American Youth from the Point of View of a Biologist
 Riddle, Oscar, 1877-1968.
Educational Darkness and Luminous Research
 Riddle, Oscar, 1877-1968.
Endocrine Control of Reproduction in Birds
 Riddle, Oscar, 1877-1968.
Endocrine, Regulation of Reproduction
 Riddle, Oscar, 1877-1968.
Endocrine Society Address
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Endocrines and Constitution
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Establishment of Race of Pigeons with Characteristically Large and with Characteristically Small Thyroid
 Riddle, Oscar, 1877-1968.
Fellowship Presentation to William L. Laurence, 1888-1977
1940 February 1 
 Riddle, Oscar, 1877-1968.
Fortieth Anniversary of the Scopes Trial in Tennessee
 Riddle, Oscar, 1877-1968.
Genetics and Developmental Forces and the Optimum in Man
 Riddle, Oscar, 1877-1968.
Genetics and Human Behavior
 Riddle, Oscar, 1877-1968.
Germinal Basis of Development (Heredity)
 Riddle, Oscar, 1877-1968.
Glandulas Endocrinas y la Constitucion
 Riddle, Oscar, 1877-1968.
Hempstead Address
 Riddle, Oscar, 1877-1968.
Hitherto Unknown Function of the Thymus
 Riddle, Oscar, 1877-1968.
Hormone Therapy Viewed by the Research Physiologist
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Hormones and Human Inequality
 Riddle, Oscar, 1877-1968.
Humanist of the Year Acceptance Speech
 Riddle, Oscar, 1877-1968.
Internal Secretions in Evolution
 Riddle, Oscar, 1877-1968.
Introducing J. B. S. (John Burdon Sanderson) Haldane, 1892-1964
 Riddle, Oscar, 1877-1968.
Is Organized Religion the Source of Today's Moral Impasse?
 Riddle, Oscar, 1877-1968.
Items in the Emergence of the NABT
 Riddle, Oscar, 1877-1968.
Life-Science and Man
 Riddle, Oscar, 1877-1968.
Life Sciences and Modern Man
 Riddle, Oscar, 1877-1968.
Life Sciences in Everyday Living
 Riddle, Oscar, 1877-1968.
Metabolic Theory of Sex and its Reversibility in the Ova of Doves and Pigeons
 Riddle, Oscar, 1877-1968.
Metabolism and the Newer Aspect of the Sex Problems
  2 folder(s)
 Riddle, Oscar, 1877-1968.
Metodos y Resultados de Medicion de Tasa
 Riddle, Oscar, 1877-1968.
Moods, Men, and Understanding
 Riddle, Oscar, 1877-1968.
Must We Fail in Science Education?
 Riddle, Oscar, 1877-1968.
National Association of Biology Teachers Address
 Riddle, Oscar, 1877-1968.
Neglected Sciences in Modern Life
 Riddle, Oscar, 1877-1968.
New Data on the Relation of Metabolism in Sex
 Riddle, Oscar, 1877-1968.
New Light on the Physiology of Sex
 Riddle, Oscar, 1877-1968.
New National Interest in High School Science
 Riddle, Oscar, 1877-1968.
Note on Professor Whitman's Unpublished Work
 Riddle, Oscar, 1877-1968.
On Endocrines and Organisms
 Riddle, Oscar, 1877-1968.
On the Humanist Alternative
1966 April 29 
 Riddle, Oscar, 1877-1968.
On the Origin of the National Association of Biology Teachers
 Riddle, Oscar, 1877-1968.
On the Thyroid Data of Table and Polygons for Thyroid
 Riddle, Oscar, 1877-1968.
Opportunity and Obligation of the National Association of Biology Teachers
 Riddle, Oscar, 1877-1968.
Origin of Good and Evil
 Riddle, Oscar, 1877-1968.
Orlando, Florida, Junior High School Address
 Riddle, Oscar, 1877-1968.
Parental Behavior and Prolactin: Three Decades of Testing that Association
 Riddle, Oscar, 1877-1968.
Participacion de Hormonas Hipofisiarias en el Metabolismo Graso e Hidrocarbonado
 Riddle, Oscar, 1877-1968.
Personal Philosophy
 Riddle, Oscar, 1877-1968.
Personal View of Items
 Riddle, Oscar, 1877-1968.
Plant City Lions Club, Brief for Talk
 Riddle, Oscar, 1877-1968.
Preliminary Impressions and Facts from a Questionnaire on Secondary School Biology
 Riddle, Oscar, 1877-1968.
Press Releases, Clippings, etc.
 Riddle, Oscar, 1877-1968.
Prolactin, a Product of the Anterior Pituitary
 Riddle, Oscar, 1877-1968.
Prolactin and Parental Behavior: Introduction
 Riddle, Oscar, 1877-1968.
Prolactin in Vertebrate Function and Organization
 Riddle, Oscar, 1877-1968.
Prolactin or Progesterone as Key to Parental Behavior: A Review
 Riddle, Oscar, 1877-1968.
Promise of Endocrinology
 Riddle, Oscar, 1877-1968.
Proofs and Implications of Complete Sex-Transformation in Animals
 Riddle, Oscar, 1877-1968.
Recent Knowledge of Sex
 Riddle, Oscar, 1877-1968.
Recent Studies on the Relation of Metabolism to Sex
 Riddle, Oscar, 1877-1968.
Recognition and Removal of Barriers to Effective Teaching of Secondary School Biology
 Riddle, Oscar, 1877-1968.
Relative Claims of Natural Sciences and of Social Studies
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Role of Endocrines in Development
 Riddle, Oscar, 1877-1968.
 Riddle, Oscar, 1877-1968.
Science in Education in a Democracy
 Riddle, Oscar, 1877-1968.
Science Seminar Abstract
 Riddle, Oscar, 1877-1968.
Seasonal, Endocrine, and Temperature Factors
 Riddle, Oscar, 1877-1968.
Serving its Time
 Riddle, Oscar, 1877-1968.
Sex and Intersex in Pigeons
 Riddle, Oscar, 1877-1968.
Sex Control and Known Correlations in Pigeons
 Riddle, Oscar, 1877-1968.
Sex in a Fraternity of Pigeons Obtained from an Interfamily Cross
 Riddle, Oscar, 1877-1968.
Should Euthanasia be Made Lawful?
 Riddle, Oscar, 1877-1968.
Some Aspects of Sexual Difference in Prenatal Growth and Death
 Riddle, Oscar, 1877-1968.
Some Concurrent Changes Involving the Newer Aspect of the Sex Problem
 Riddle, Oscar, 1877-1968.
Some Interrelations of Sexuality, Reproduction, and Internal Secretion
 Riddle, Oscar, 1877-1968.
Some Products and Functions of the Anterior Pituitary Gland
 Riddle, Oscar, 1877-1968.
Special Contribution of Developmental Mechanics to the Thought and Purpose of the Man of Tomorrow
 Riddle, Oscar, 1877-1968.
Spreading Spark of Life
 Riddle, Oscar, 1877-1968.
Studies on Pituitary Functions
 Riddle, Oscar, 1877-1968.
Sustaining Luxuries of the Mind
 Riddle, Oscar, 1877-1968.
To a Few Close Relatives
 Riddle, Oscar, 1877-1968.
Topics to Emphasize
 Riddle, Oscar, 1877-1968.
United States Ambassador to the Vatican
 Riddle, Oscar, 1877-1968.
University Club of Chicago Address
 Riddle, Oscar, 1877-1968.
Unleashing of Evolutionary Thought
 Riddle, Oscar, 1877-1968.
Visit to India
 Riddle, Oscar, 1877-1968.
What the Race Needs
 Riddle, Oscar, 1877-1968.
Whitman Manuscript Catalogue
 Riddle, Oscar, 1877-1968.
Why Learning?
 Riddle, Oscar, 1877-1968.
Words at Funeral for Seymour Riddle, 1868-1944
 Riddle, Leona Lewis, 1896-1968. Riddle, Oscar, 1877-1968.
 III. Research Data & Notes
 Birds, Wild
 Birds, Wild. Data, Female
 Birds, Wild. Data on Reproductive Organs
 Birds, Wild. Data on Reproductive Organs of Females of Various Species
 Birds, Wild. Data on Reproductive Organs of Males of Various Species
 Birds, Wild. Rough Data on Reproductive Organs
 Breeding Records, Egg Records
 Breeding Records of Pigeons
 IV. Graphics
1905-1906 2 item(s)

A selection of graphics available in the Oscar Riddle papers.

  25 item(s)
ca. 1905 1 item(s)

Abstract: Profile watercolor of a pigeon perched on a branch.

Access digital object:

 Pigeon, adult male, Zenaida x Zenaidura hybrid.
1906 1 item(s)

Abstract: Watercolor of pigeon perched on rock.

Access digital object: