Raymond Pearl Papers, American Philosophical Society

Table of contents

Abstract

Raymond Pearl spent the majority of his academic career (1918-1940) at Johns Hopkins University, where he was Professor of Biometry and Vital Statistics and Director of the Institute of Biological Research. Founder of the Quarterly Review of Biology and Human Biology, he made significant contributions in the areas of biology, genetics, eugenics, and statistics. The Pearl Papers includes correspondence as well as notebooks, scrapbooks, diplomas, photographs, and 33 volumes of diaries. There is significant correspondence with his wife, Maud (ca. 500 letters), and mother, Ida May (ca. 300 letters), particularly for the years 1895-1934. Of special note is Pearl's correspondence with his friend, colleague, and fellow Baltimoreian, H. L. Mencken (ca. 500 letters). The collection contains important information on the American Association of Physical Anthropologists, The Baltimore Sun, the Birth Control Federation of America, Dartmouth College, the International Institute of Statistics, Johns Hopkins University, and the National Academy of Sciences.

Background note
Scope & content
Administrative information
Additional information
Added entries
Contact information
Collection overview
- Series I - Correspondence, , 1895-1940
- Series II - Ida May Pearl correspondence, , 1895-1934
- Series III - Maud Pearl correspondence, , 1901-1929
- Series IV - Bound volumes, , 1902-1940
- Series V - Photographs, , 1897-1940
Collection inventory
- Series I. Correspondence
- Series II. Ida May Pearl Correspondence
- Series III. Maud Pearl Correspondence
- Series IV. Bound volumes
- Series V. Photographs

Background note

An early and influential advocate for the importation of statistics into biological analysis, Raymond Pearl was a pioneer in American population biology and ecology. The son of Frank Pearl, a grocery clerk and shoe factory foreman, and Ida May McDuffee, Pearl attended Dartmouth College (A.B., 1899) and the University of Michigan (Ph.D., 1902). Like many students of his generation, Pearl traveled abroad after receiving his doctorate to strengthen his education, studying first at the University of Leipzig in 1905, and then under Karl Pearson at University College London (1905-1906). It was Pearson who quickened Pearl's interests in quantitative analysis and fostered his first efforts to apply statistics to population genetics. He married Maud Mary Dewitt, a fellow student at Michigan, and long his collaborator, in 1903.

Pearl's first academic appointments upon returning to the States were as an instructor of zoology at the University of Pennsylvania (1906-1907) and as chair of the Department of Biology at the Maine Agricultural Experiment Station (1907-1918). Befitting his position in Maine, Pearl was engaged primarily in applied research in the genetics of poultry and cattle. Through studies aimed at increasing the productivity of egg-laying in chickens, he turned from an analysis of the inheritance of individual traits to patterns of inheritance in populations. Recognizing, as Mendelian theory predicted, that individuals often did not express the same traits as their parents, Pearl began to study population-level characteristics such as birth rate, death rate, and population size, and to reconceptualize the genetic and environmental dynamics of evolutionary change. His work took him variously into a reanalysis of Malthus' predictions on population density and into direct conflict with the tendencies of much eugenic research to focus on individual traits and individual couples. By 1915, his reputation had grown widely enough in scientific circles to merit election to the American Philosophical Society and, in 1916, to the National Academy of Sciences.

Leaving Maine to become Professor of Biometry at Johns Hopkins in 1918, Pearl entered into the most productive period of his career. At Hopkins, where he served variously as Professor of Biology (1923-1940) and as statistician at the Johns Hopkins Hospital (1919-1935), Pearl turned a statistical eye toward the dynamics of human populations, producing remarkably accurate and durable estimates of changes in world population based upon the best-guess estimates for birth rate and longevity. More controversially, based upon U.S. Census data from 1920, he and Lowell J. Reed theorized that the logistic (sigmoidal) curve was in effect a law of nature describing population growth: after a slow initial period of expansion, populations enter a phase of exponential growth until the they reach the carrying capacity of the environment and level off. Although recognized as a useful heuristic for exploring population dynamics, Pearl's aggressive promotion of the logistic curve and his truculence in its defence alienated many of his colleagues. In other research, Pearl experimented with the factors influencing population dynamics in Drosophila melanogaster, turned to estimates of life expectancy based upon occupation and personal habits, and entered into various statistical aspects of reproductive behavior. An inveterate opponent of most eugenic policies, and critic of eugenic research, he was nevertheless a strong and vocal supporter of birth control and population planning.

Using funds provided by the Rockefeller Foundation, Pearl established the Institute for Biological Research at Johns Hopkins in 1925, heading it throughout its five year existence. He was also active in numerous professional organizations, serving as president of the International Union for Scientific Investigation of Population Problems (1928-1931), the American Association of Physical Anthropologists (1934-1936), and the American Statistical Association (1939),and helping to found and edit the Quarterly Review of Biology in 1926 and Human Biology in 1929. An agile and prolific writer, Pearl wrote 17 books and nearly 700 articles during his career on a extraordinary range of subjects.

Scope and content

A major resource for study of American biometry in the first half of the 20th century, the Pearl Papers contain 14 linear feet of the professional correspondence of Raymond Pearl, longtime professor at Johns Hopkins University, 1.5 linear feet of correspondence with his mother, and one linear foot of letters from Pearl to his wife Maud, concentrated in the period before their marriage, 1897-1899. The Pearl Papers are a rich resource for study of the development of population genetics and population biology during the 1920s and 1930s, as well as biological statistics and biometry, and they contain valuable information on both eugenics and birth control.

The collection is divided into five series:


Series I	Correspondence, 1895-1940	30 boxes; 15 linear feet
Series II	Correspondence with Ida May Pearl, 1895-1934	2 boxes, 1 linear foot
Series III	Correspondence with Maud Pearl, 1901-1929	3 boxes; 1.5 linear feet
Series IV	Bound volumes, 1902-1940	43 vols.; 1.5 linear feet
Series V	Photographs, 1897-1940	15 items, 0.25 linear feet

Administrative information

Restrictions

Correspondence from H.L. Mencken may not be consulted without permission of Mencken's estate.

Provenance

Acquired, 1973.

Preferred citation

Cite as: Raymond Pearl Papers, American Philosophical Society.

Other finding aids

The Pearl Papers are also described in Bentley Glass's A Guide to the Genetics Collections of the APS.

Additional information

Separated material

Photographs are housed with graphic materials.

Related material

A significant quantity of Pearl correspondence appears in the papers of Charles B. Davenport (239 items) and Herbert Spencer Jennings (278 items).

References

There is a biographical memoir in APS Year Book 1940.

Other descriptive information

B P312