A Guide to the Genetics Collections at the APS
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Herbert Spencer Jennings Papers

b. April 8, 1868, Tonica, Illinois. d. April 14, 1947, Santa Monica, California. Father, George Nelson Jennings, physician. Mother, Olive Taft Jenks (J.). m. (1) Mary Louise Burridge, June 8, 1898; son, Burridge. (2) Lulu Plant Jennings, October 21, 1939.

School teacher, Laurens, Iowa, 1886; Trout, Illinois, 1887; Putnam County Quaker District, Illinois, 1888-89. Illinois State Normal School, 1887-88. Asst. professor, botany and horticulture, Texas Agricultural and Mechanical C., 1889-90. U. Michigan, 1890-93, B.S.; asst., zoology, 1892-94. Harvard University, asst. zoology, 189495; M.A., 1895; Morgan Fellow, 1895-96; Ph.D., 1896; Parker Traveling Fellow, U. Jena (Germany) and Naples Zoological Station, 1896-97. Professor of botany and bacteriology, Montana State Agricultural and Mechanical C., 1897-98. Instructor, zoology, Dartmouth C., 1898-99. Instructor, zoology, U. Michigan, 1899-1901; asst. professor, 1901-03. Research assistant, Carnegie Inst. of Washington, Naples Zoological Laboratory, 1903-04. Asst. professor, zoology, U. Pennsylvania, 1903-06, Assoc. professor, physiological zoology, Johns Hopkins U., 1906-07; prof. experimental zoology, 1907-10; Henry Walters Professor and Director of the Zoological Laboratory, 1910-38; emer. prof, 1938-47. Visiting prof, U. California, Los Angeles, 1939-40; research associate, 1940-47.
Act. Director, U.S. Fish Commission, Biological Survey of the Great Lakes, 1901; Director, 1902. Statistician, U.S. Food Administration, Sugar Division, 1917-18. Visiting lecturer, Stanford U., 1925; 1933. Visiting prof., Keio U., Tokyo, 1931-32. Terry Lecturer, Yale U., 1933. Vanuxem Lecturer, Princeton U., 1934. Eastman Visiting Prof, Oxford U., 1935-36. Leidy Lecturer, U. Pennsylvania, 1940. Fatten Lecturer, Indiana U., 1943.

BIOG.
Conklin, E.G., Ybk. Amer. Philos. Soc. 1947:258-262. Geiser, S.W., Bios 5(1):3-18 (1934). Lovejoy, A.O., Johns Hopkins Alumni Mag. 10(2):81-86 (1922). Jennings, H.S. "On the Advantages of Growing Old," Johns Hopkins Alumni Mag. 10(4):241-251. Sonneborn, T.M., Dict. Amer. Biog: Sonneborn, T.M., Biog. Mem. Natl. Acad. Sci. (U.S.A.) 47:143-223 (1975). Amer. Men of Sci. For others, see Sonneborn, 1975.

BIBLIOG.
Almost complete bibliography (177 items) in Sonneborn, 1975. Twelve additions, as follows: "Modern science and the illusions of Professor Bergson." J. Philos., Psychol. and Scientific Methods 10:353-58, 1913. "Mendel, the scientist." Fleur de Lis, April 1923:1-7. "Leidy's zoological work." Scient. Monthly 18:427-32, 1924. "Review: Crime and Destiny, by Johannes Lange." Nation, Jan. 14, 1931. "Eugenics." Encyclop. Soc. Sci., 617-631, 1931. A contribution (unascertained) to the Independent Woman, 1934. "Review: Heredity and Disease, by O.L. Mohr." Survey, 71:187, June, 1935. "Biological recommendations for the ills of mankind. Review of Man the Unknown, by Alexis Carrel." Nation, Dec. 25, 1935. "Review: We Europeans, by Julian Huxley and A.C. Haddon." New York Herald Tribune, Books, p. 1, Feb. 23, 1936. "Review: Fearfully and Wonderfully Made, by H. von Eulenberg Wiener." Yale Rev. 27:827, 1938, " Raymond Pearl." Genetics 26:ix-xi (unpag.), 1941. "Individuality. A review of The Biological Basis of Individuality, by Leo Loeb." Science 101:509-10, 1945.

BOOKS AND MONOGRAPHS.
Ten, as follows: The Anatomy of the Cat (with J. Reighard); and supplement, Dissection of the Cat (with J. Reighard and J. Rush Elliott), 1901. Contributions to the study of the behavior of lower organisms, 1904. Behavior of the Lower Organisms, 1906. Reprinted, 1923, 1963. German translation, 1910. Life and Death, Heredity and Evolution in Unicellular Organisms, 1920. Prometheus, or Biology and the Advancement of Man, 1925. Genetics of the Protozoa, 1929. The Biological Basis of Human Nature, 1930. The Universe and Life, 1933. Genetics, 1935. Genetic Variations in Relation to Evolution, 1935.

SCIENTIFIC AND PROFESSIONAL OFFICES.
Pres., Amer. Soc. Zool., 1909. Pres., Amer. Soc. Naturalists, 1910. Chairman (first), Genetics Soc. Amer., 1922. V.pres., Sect. F (zool.) Amer. Assn. Advancement of Sci., 1925; com. of 100 on scientific research. Trustee, Marine Biol. Lab., Woods Hole, 1905-38. Academic Council, Johns Hopkins U., 1912-33. Council, Amer. Philos. Soc., 1918-24; 1928-36. Pres., Johns Hopkins chapter Phi Beta Kappa, 1928. Educ. Adv. Ed., Guggenhelm Found., 1928-40. Natl. Acad. Sci., chmn. sect. zool. & anat., 1928-31; council, 1934-40; chmn. Bache Fund, 1928-31. Natl. Res. Council, Div. Biol. & Agric., 1920-25.

HONORS AND AWARDS.
LL.D., Clark U., 1909; Oberlin C., 1933; U. Pennsylvania, 1940; U. Chicago, 1941; U. California, 1943. Sc.D., U. Michigan, 1918; U. Pennsylvania, 1933. A.M., Oxford U., 1935. Member, Amer. Philos. Soc., 1907; Natl. Acad. Sci., 1914. Walker Prize, Boston Society of Natural History, 1896; 1908. Leidy Award, Philadelphia Acad. Natural Sciences, 1925. Inscription of name, Buhl Hall of Science, Pennsylvania State C. for Women, 1931. Corr. memb., Acad. Nat. Sci., Philadelphia; Russian Acad. Sci.; Soc. de Biol. de France; Zool. Sec. London. Hon. Fellow, Roy. Micros. Soc., London; Roy. Soc., Edinburgh.

EDITORIAL WORK.
Ed. Bd., Biol. Bull., Genetics, Human Biol., J. Exp. Zool., J. Comp. Psychol.

The Jennings Papers
A diversified collection of great size. 19 boxes of correspondence and miscellaneous papers + separate file of 85 vols. of diaries, manuscripts (many unpub.), notebooks, lecture notes, syllabi of courses taught by J. at Johns Hopkins U., scrapbooks, memorabilia, etc.

Herbert Spencer Jennings came from a family that prized education highly. His father was a physician and an evolutionist philosopher. But the family's economic means did not extend to providing money for tuition and board away from home. After graduating from high school in the little northern Illinois town of Tonica, in 1886, Jennings was thrown on his own resources. That difficulty accounts for the successive efforts made by the young man to earn enough by teaching in one-room country schools to enable him to enter a college. Jennings was accustomed to self-reliance. He had learned to read by the age of three, read a biology book at age four, and a considerable amount of natural history and Shakespeare by age five. His father's love for the works of Herbert Spencer, Charles Darwin, Thomas Henry Huxley, Tyndall, and the like was passed on to Herbert, his oldest son .

When Herbert's favorite high school teacher, Thomas Brunk, received an appointment as a professor of botany and horticulture at Texas Agricultural and Mechanical College, he persuaded Jennings to take a post as assistant professor at $600 for the academic year. It was a fine salary for those days, but the situation proved untenable because of internal faculty wrangling involving Jennings's sponsor. The young "professor" who had never attended college himself learned a great deal of botanical knowledge and published his first scientific paper while at College Station, one on local parasitic fungi, including some new species.

In the fall of 1890 Jennings entered the University of Michigan and found Jacob Reighard's course in general biology most stimulating. With the aid of an assistantship in zoology, he was able to continue his program, with the clear intention of becoming a biologist. Along with work in that discipline, Jennings found philosophy greatly to his taste, especially the ideas of John Dewey. Letters from this period to his cousin Eva Curtis reveal much of his absorption in his studies and his shame at having little money to keep up an appearance that would do him credit. By working during the summer of 1892 for the Michigan Fish Commission he helped his family to send his younger brother George to the University of Michigan also. It was during this summer's work that Jennings made his first deep acquaintance with the rotifers, on which he was to spend so much fruitful research effort over the ensuing years. After graduating in 1893, Jennings joined Professor Reighard in an undertaking to make a biological survey of the Great Lakes. During 1893-94, when he commenced graduate study at Michigan, Jennings also collaborated with Reighard in teaching mammalian anatomy, based on the dissection of the cat. This experience led to the joint book which they later published, and which for many years brought modest royalties to Jennings, as it was widely used. A young woman student, Mary Louise Burridge, also captured his attention, and soon they were deeply in love and affianced. Nevertheless, Jennings felt that he had to leave Michigan and remove himself from the shadow of Reighard. He was admitted to Harvard University for graduate study in 1894.

At Harvard, under Professor Mark, Jennings pursued his studies of the early cell divisions and embryology of a selected rotifer, Asplanchna. He was greatly stimulated by his classes with a young instructor, Charles B. Davenport, about whom he wrote revealingly to his fiancée; and also by E. B. Castle, a fellow graduate student in the department, and whom Jennings regarded as the brightest of them all. George H. Parker, another of his instructors, also stimulated Jennings. But perhaps he owed the profoundest growth in knowledge and the command of his discipline to meetings with his fellow graduate students Castle, Mayr, Neal, and Goto. Jennings worked during the summer of 1895 at the seaside Agassiz Laboratory at Newport, Rhode Island, making additional friends. His rapid progress was marked by the M.A. degree, received after his first year at Harvard, and the coveted Ph.D. degree just a year later. During one year, he taught as an assistant; but during the second year he had a fellowship that freed him entirely for devotion to research. The young mid-westerner also found time and opportunity to enjoy the music and theater of Boston, and he gained greatly in cultural breadth. Letters to his family, and especially the many to his fiancée, reveal his thoughts on religion and philosophy as well as on biological matters.

Having won Harvard's Parker Traveling Fellowship, as well as the Walker Prize of the Boston Society of Natural History, Jennings was enabled to go to Europe for a year of postdoctoral education and research. After spending a summer in the Hart Mountains learning German, he decided to go to Jena to work with Verworn on the reactions of animal cells to simple physical stimuli. Verworn introduced Jennings to the ciliated protozoan Paramecium, which orients itself to an electric current, and Jennings proceeded to study many of its other tropisms. Again, his reactions to the great men of science he met, Haeckel and Liebmann, for example, are reported in great detail to his fiancée in his letters. From Jena, Jennings went to spend some months at the famous Naples Zoological Laboratory, where he became a friend of Hans Driesch, met many other famous German biologists, and absorbed a great deal of Italian music and scenery. Because of his reluctance to remain any longer so separated from his fiancée, Jennings decided not to apply for a second year of European study, and sought a position in the academic world in the United States. The best he could obtain was a position as instructor in botany and bacteriology at Montana State College in Bozeman, remote geographically from all American centers of learning and scientific research at the time, and in a state of deplorable physical development.

With characteristic energy, Jennings threw himself into his tasks and made a good reputation for himself. At the end of the year he received an offer to fill a temporary vacancy at Dartmouth College. He accepted, and with a firm belief in his rising reputation and good fortune, he and Mary Louise Burridge were married. For the summer, he joined Reighard in a Biological Survey of the Great Lakes, sponsored by the U.S. Fish Commission. Mary Louise, an accomplished artist, went with him to provide drawings of their finds, and thus they spent their honeymoon.

The Dartmouth year was a busy one. Jennings completed a number of publications, including a monograph on the rotifers of the United States, the drawings for which were made by Mary Louise. The University of Michigan then offered him an instructorship in zoology, which he accepted. He took with him from Dartmouth his first graduate student, Raymond Pearl. But Jennings soon felt that at Michigan he was trapped. His teaching, and extra hours substituting for Professor Reighard, who had had a breakdown, left him no time for research. Public pressure on the university because of the exodus of many of its best professors led to a promotion for Jennings, an increase in salary, and a position as Acting Director, and then Director, of the Biological Survey of the Great Lakes. The Carnegie Institution of Washington which Jennings had served as a biological adviser, came to the rescue with a grant enabling him to go the Naples Zoological Laboratory for the year; and the University of Pennsylvania offered him an assistant professorship with an initial year's leave of absence to permit the year in Naples. That year was delightful and productive, and is amply described in the joint diary which was kept by Jennings and his wife. They made important new friends, including Hans Spemann, and Jennings's investigations of the behavior of the protozoans and other lower animals were published in a Carnegie Institution monograph that firmly established his reputation as a gifted scientist.

Jennings was to stay only two years in Philadelphia, but they were years of concentrated effort, calling for public lectures as well as his teaching and research. One summer was spent at the Tortugas Laboratory with Jennings's Harvard friend Mayr; and a second summer introduced the Jenningses to the Woods Hole biological community. Jennings lectured on his studies of animal behavior of the lower organisms, and regained some of the good health he had lost from overwork. He was invited by E.B. Wilson to repeat his lectures at Columbia University in the fall and to let the Columbia University Press bring out the investigations in book form. This success led to a further invitation to repeat the series of lectures at Goucher College in Baltimore, and Professor Brooks of the Johns Hopkins University was so impressed that he immediately extended to Jennings an invitation to come to Johns Hopkins as an associate professor, at what, for those days, was a fine salary of $3000 per annum. Even more important was the promise that Jennings would become chairman of the Department of Zoology when Brooks retired. Just a year later Jennings became a full professor, at the institution where he was to remain for thirty-two years, until he reached the age of retirement. When Brooks died, in 1910, the university was about to appoint Thomas Hunt Morgan to succeed him; but Jennings confronted the president of the university with the letter from Brooks in which he had been promised the succession. The promise was honored, and Jennings not only became the head of the department but was named the Henry Walters Professor of Zoology, an endowed chair, as well. Tracy M. Sonneborn, who became Jennings's most distinguished student and who wrote the fine memoir of Jennings's career for the Biographical Memoirs of the National Academy of Sciences, on which this abbreviated sketch is very largely based, stated in his memoir of Jennings that this was a profound lesson to Jennings to commit all agreements to writing. It was a lesson he never forgot, and impressed upon his students and colleagues. Warm respect and fine personal relations within the department were the result.

In his first year at Johns Hopkins, Jennings shifted his main field of investigation from the behavior of the lower organisms to their heredity. He continued to use Paramecium as the animal for his investigations, building on the novelty, in comparison with higher animals, that its common form of reproduction is asexual mitotic fission -- so that clones of genetically identical individuals can be easily raised and subjected to various regimens and to physical or biological factors that might alter the genes. Such species are eminently suited to study the question of the inheritance of acquired characteristics, which Lamarck had proposed as a basis for evolutionary change and which Charles Darwin had accepted as a contributory mechanism under the concept of "use and disuse." Jennings, by 1910, had firmly established the genetic uniformity and constancy of the clone, and had shown that alterations produced in the individuals by diverse environmental conditions were not inherited after the environmental causes were removed. He introduced into the heredity of unicellular organisms the concepts of the modifiable phenotype contrasted with the enduring genotype, concepts that W. Johannsen had first enunciated after experiments on pure lines of beans. Jennings's students, under his guidance, were to extend these ruling concepts to asexually reproducing multicellular animals.

Jennings himself, after 1910, turned to the analysis of heredity following sexual reproduction (conjugation) in the paramecia. In this effort he was blocked by his inability to make the different stocks of paramecia conjugate. It was not until a quarter of a century had passed that Sonneborn surmounted this difficulty by finding the existence of mating types within each species. Only individuals of different mating types will conjugate and undergo meiosis, during which the chromosomes, and parts of chromosomes, recombine and reassert into different genotypes. Nevertheless, by capitalizing upon conjugation whenever it did occur fortuitously, Jennings did succeed in showing that conjugation led to the production of numerous hereditarily diverse clones.

During the years 1911-24 Jennings devoted considerable attention to mathematical aspects of heredity. Many manuscripts and volumes among the Jennings Papers are devoted to this subject. One subject, of particular importance at the time, was a mathematical demonstration that the complex data from Drosophila breeding not only fitted closely to the expectation derived from the theory of the linear arrangement of genes in chromosomes, but could hardly be reconciled with any other theory. This analysis of crossing over and interference data, presented in a Woods Hole summer lecture, delighted Morgan and his Drosophila students. It was eventually published in the Proceedings of the National Academy of Sciences in 1923.

Jennings was persistently interested in the process of evolution and its causal factors. He found that within a clone, otherwise so constant in characteristics, evolution might be caught "in progress" by selecting for small hereditary differences in specific characters. For this purpose Jennings went to a shelled ameboid type of protozoan, Difflugia. Jennings and his students looked for mutations that would bring about an abrupt, inherited variation in type. He especially hoped to find out whether mutations of genes were the sole basis of such evolutionary changes, or whether other, still undiscovered, mechanisms were involved. Many of the notes for his lectures to his graduate course in genetics and evolution, from the 1930s, are preserved in the papers. They show his meticulous attention to accuracy and clarity of expression. Unlike many teachers, he wrote out in rough form, but in complete good style, each of his lectures, and read them to his classes. The impromptu delivery of scientific matter was too casual to appeal to him.

When Tracy M. Sonneborn discovered the mating types of Paramecium in 1937, and thereby made it possible -- and easy -- to crossbreed different varieties and to analyze the results in Mendelian terms, Jennings was delighted. He thereupon decided to select a new species, P. bursaria, with which to work, so as to leave P. azlrelia to Sonneborn. Just a year from the age of retirement at Johns Hopkins University, he embarked with accustomed zeal on this new line of work. In the remaining eight years of his life he accomplished a vast amount of significant research on P. bursaria. Thirteen technical papers and almost as many more of a broader kind resulted-reviews, contributions to symposia, general articles on inheritance in the Protozoa and its applications to a knowledge of heredity in general, of evolutionary processes, and of "the biological bases of human nature."

As Jennings matured, his social conscience became manifest in many ways. One of the first, and most important of these, was his rebuttal of Harry H. Laughlin's claim that immigrants from southern and eastern Europe into the United States were genetically inferior to those from western and northern Europe, and that for the sake of the eugenic future of America immigration laws should restrict the admission of persons from southern or eastern Europe. Jennings was shocked by Laughlin's poor statistical calculations. He disproved the claim made by Laughlin by showing that the immigrants coming from at least one western country were at the bottom of the list of qualifications in IQ and criminality, whereas at least one nation from southern Europe was close to the top in desirable qualifications. He made an appearance as a witness to that effect before the House subcommittee on immigration, and at about the same time resigned from responsible association with the Eugenics Society. In the immediate case, his representations seem to have had little influence on Mr. Johnson, chairman of the House subcommittee, or on the passage of the biased legislation. The effect on Jennings himself was to invigorate his social conscience, and to show in every way by public lectures, articles in newspapers and popular magazines, and book reviews, what good scientific knowledge of the time could truthfully say about human heredity. He based his Jeffersonian idea of democracy on the biological idea that every genotype needs an optimum kind of environment in order to realize its full potentialities -- and not necessarily the same exact kind of optimum environment for everyone. Even on such a delicate subject as the consequences of racial intermixture, he was forthright. There is no scientific evidence that the ultimate effects of racial interbreeding are harmful, he said. Recombination and reassortment of genetic elements will take place. Some newly arising genotypes will be less biologically fit or less socially well adapted and will in the long run be weeded out. Others may well be superior to anything that could be found in the original breeds or races, particularly in adaptability to novel kinds of environment. It will be an exciting time in which to live, he asserted. Jennings's views on this subject have been covered in more detail in an article based in part on findings in the Jennings Papers (see B. Glass, "Geneticists Embattled: Their Stand against Rampant Eugenics and Racism in America during the 1920s and 1930s," Proc. Amer. Philos. Soc. 130:130-154, 1986. The specific lecture addressed to Jennings's graduate seminar at Johns Hopkins on the effects of racial crossing, in 1932, and previously to an international conference on population held in Baltimore in 1928 is therein discussed more fully, and is referenced to footnote 37.). In his little book Prometheus, or Biology and the Advancement of Man (1925), in The Biological Basis of Human Nature (1930), in The Universe and Life (1933), and in innumerable shorter articles for the general public Jennings declared his biological philosophy. His early work on the behavior of lower organisms was significantly tied to his interests in heredity and evolution, aging and death; and he grew more involved in the personal and social human consequences of genetics as the years passed.

Jennings was in tremendous demand as a public lecturer. This is quite evident from the many important visiting lectureships he held and the visiting professorships in Japan and Oxford. That fact may seem a bit surprising when we consider that he always wrote every lecture out in detail, and read it to his audience. His delivery was expressive, but definitely not dramatic. Evidently, his great appeal rested primarily on his depth of knowledge and his sincerity. He was a great humanist.

Mary Louise Jennings died in 1938, leaving her husband in great loneliness, especially since the loss occurred just after his retirement from Johns Hopkins. A year later, however, he found a scientific refuge at the University of California at Los Angeles, where he continued his work on Paramecium. Here, too, he found his recently widowed sister-in-law, Lulu Plant Jennings, and his niece Carolyn Jennings, who together provided solace. Herbert Spencer Jennings and Lulu Jennings were married in 1939 and he found a new happiness in his work and his home in the final years of his life. Sonneborn has rated the scientific value of his last researches, done with clones of P. bursaria according to their mating types, as "unsurpassed in lasting value by any other major investigation of his life, except for his first experimental researches on cell behavior."

His influence as a teacher was very great indeed. In addition to Raymond Pearl, already mentioned, a number came to him to study animal behavior, including Karl Lashley; others to study unicellular organisms, including Robert Hegner, William H. Taliaferro, S. O. Mast, Tracy M. Sonneborn, Ruth Stocking (Lynch), and Richard Kimball; still others to contribute to biostatistics, for example, F. M. Root.

Jennings devoted a great deal of time and energy to the demands of professional organizations. In particular, there was his stint of war work during World War I, when he served in Washington, under his own former graduate student Raymond Pearl, as Statistician of the Sugar Division of the U. S. Food Administration. He was a longtime trustee of the Marine Biological Laboratory at Woods Hole, and a member of the governing councils of the American Philosophical Society (8 years), the National Academy of Sciences (6 years), and the Academic Council of Johns Hopkins University (20 years). He also served the National Research Council, the Guggenheim Foundation, and the American Association for the Advancement of Science in significant capacities, as well as the scientific societies of which he became a president. His dispassionate yet critical judgment was highly prized by his colleagues. It is simply amazing how much he contributed to the scientific life of his times. Yet today, in all probability, he is not regarded, even by geneticists, so highly as in his own lifetime. This is mainly because his views, once at the center of eugenic and social controversy, are now generally accepted as a part of American social philosophy; and in part because his devotion to the study of heredity in unicellular animals has become a scientific backwater in these days of molecular biology. Nevertheless, in the history of American biology he must rank among the foremost in the first half of the twentieth century.

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