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Dates: b. 1859; 1884 to USDA; 1895 to Harvard; 1914 to Princeton; retired 1929; d. 1934
Locations: Dir. Pathological Laboratory, USDA Bur. of Animal Industry (1884‑1895); Prof. of Bacteriology, Columbian University (G.W.) (1886‑1895); Pathologist and Dir. of Laboratories, Mass. State Board of Health (1896‑1915); Professor of Applied Zoology, Harvard (1895); Professor of Comparative Pathology, Harvard Medical School (1896‑1915); Bussey Institute Laboratory for Antitoxin Production; Board of Directors, Rockefeller Inst. for Medical Research (1901); Dir. Dept. of Animal Pathology, Princeton (1915‑1929)
Training: BS at Cornell; MD 1883 Albany Medical College; one semester at Hopkins in 1882
Fields: medical; veterinary; milk; water; biology
Publications: with D.E. Salmon, "Bacterium of Swine‑Plague," Proc. Am. Ass. Adv. Sci. 34 (1886): 303; "Parasitic Bacteria and Their Relation to Saprophytes," Am. Nat. 21 (1887): 1‑9; "Relation of Bacteriology to the Discovery and Prevention of the Causes of Infectious Disease among Man and Animals," 1888; Smith and Kilborne, "Hog Cholera: Its History, Nature and Treatment," USBAI (1889); with V.A. Moore, "The Hog Cholera Group of Bacteria," Centr. Bakt. 16 (1894): 231‑241; "Comparative Study of Bovine Tubercle Bacilli and of Human Bacilli from Sputum," J. Exp. Med. 3 (1898): 451‑511; "Thermal Death Point of Tubercle Bacilli in Milk," Journal of Experimental Medicine 4 (1899): 217; T. Smith and E.W. Smille, "Note on the Coccidia in Sparrows and their Assumed Relation to Blackhead in Turkeys," J. Exp. Med. 25 (1917): 415;
SAB Involvement: Charter SAB member; SAB council member 1900, 1902, 1904; Member SAB Comm. Standardizing Sera 1905‑; 3rd President SAB 1903; Chairman Lab. Section of APHA (1899); SAB Honorary Member 1922
Presidential Address: Untitled; published by Claude Dolman in ASM NEWS 47:6, 1981
Archive Files: D.H. Bergey, "Early Instructors in Bacteriology in the United States," J. of Bact. 2 (1917): 595‑601; Anna Sexton, "Theobald Smith: First Chairman of the Laboratory Section," AJPH‑Yearbook 41 (1951); Zinsser, "Theobald Smith, 1859‑1934," NAS Biog. Memoirs 17 (1936): 261‑303; Esmond R. Long, "History of the American Association of Pathologists and Bacteriologists," American Journal of Pathology 77 (1979); Philip Lillyer Smith, "Theobald Smith," The Land 8 (1949): 363‑368; some biography written by Frederick B. Bang, Federick F. Ferguson, and Norman R. Stoll; Paul F. Clark, "Theobald Smith, Student of Disease," J. Hist. Med. 14 (1959): 490‑514; "Letter from Dr. Smith," J. of Bacteriology 27 (1934): 19‑20; William Bulloch, "Obituary Notice of Deceased Member: Theobald Smith, 1859‑1934," J. Path. and Bact. 40 (1935): 621‑635; Simon H. Gage, "Theobald Smith, 1859‑1934," Cornell Vet. 25 (1935): 207‑228; Earl B. McKinley, "Theobald Smith," Science 82 (1935): 575‑586; Simon H. Gage, "Theobald Smith: Investigator and Man," Science 84 (1936): 117‑122; E.E. Tyzzer, "Theobald Smith," New Engl. J. of Med. 212 (1935): 168‑171; T. Mitchell Prudden, "Theobald Smith and a New Outlook in Animal Pathology," Science 39 (1914): 751‑754; ANB; DSB; “Dr. Theobald Smith’s Work in the Bureau of Animal Industry” by W. E. Cotton, 1938 (typescript in Smith Presidential File, 18pp.); obit: Harvard Medical Alumni Bulletin by S. Burt Wolbach; J. Bact. 30:1, by J. Howard Brown; JAMA 103:25; Am. J. Public Health Feb. 1935; Science 80:2086 by Charles Stockard; “Theobald Smith: Personal Reminiscences” by Thomas Ordway, Albany Medical Annals; Nat. Cyc. American Biog. 1934, 1949; “Theobald Smith, 1859-1934: Life and Work” by Claude Dolman, NY State J. Med. 69:21, 1969; “Theobald Smith: First Chairman of the Laboratory Section, 1900” by Anna Sexton, Year Book, Part II of Am. J. Public Health 41:5, 1951; obit, Arch. Path. 19: 234-238, 1935; “Theobald Smith (1859-1934), Pioneer American Microbiologist” by Claude Dolman, Perspectives in Biology and Medicine 25:3, Spring 1982; DAB; ANB; DSB
Smith was conducting post‑graduate work in histology at Cornell when Salmon of the BAI wrote to Simon Gage in 1884 at Cornell for an assistant. Smith knew no bacteriology and little pathology, being trained in the biology of the Darwin‑Huxley tradition. Smith became director of pathological laboratory at the age of 24, and within a year became the first professor of bacteriology in America. Smith, unlike most American bacteriologists, did not study in Europe. Instead, he developed techniques at home, and soon published on gelatinous media for bacteria (1883); a method of staining tubercle bacilli (1885); and the bacterial flora of the Potomac River (1885). Smith returned to Cornell in May of 1887 and May 1888 to deliver a course of lectures on "Bacteriology and its Relation to Hygiene."
In the 1880's, Salmon and Smith studied hog cholera, and in 1885 isolated and described a motile, Gram negative, easily cultivable bacillus that seemed to reproduce the disease in experimental hogs. However, a year later, they found another bacterium, this one a non-motile rod, that Loeffler had suggested caused swine plague. Moreover, Salmon and Smith found cases of hog cholera that did not reveal either organism. In an 1891 report Smith reported on cases of hog cholera that were due to one organism, both, or none. Only later did de Schweinitz and Dorset transmit hog cholera from filtered sera, implying that the bacilli were pathogenic secondary invaders.
Smith’s first internationally famous paper, in collaboration with Salmon, was in 1889, was on the microorganisms of Texas Cattle Fever and the role of the tick in the spread of the disease. He was the first to demonstrate the transmission of a disease by an external parasite, thereby providing a new approach to the study of communicable diseases. In the longer report with Kilborne in 1891, he reported on a series of experiments that the organism (Piroplasma bigeminum) could be passed from mother to offspring in ticks.
All the while, Smith emphasized the importance of studying from fresh cultures. Apparently, Smith noted the characteristics that might have been called dissociation some years later, mostly in connection with studies on the capacity of different strains of diphtheria bacilli to produce toxin. Smith also documented the intermediate forms of tubercle bacilli that spanned the gap between human and bovine types.
Smith began a short course of lectures on hygiene and bacteriology at Columbian University (GWU) in 1886, but did not teach full‑time until 1896 at Harvard. He took an interest in water bacteriology, developing the fermentation tube that adapted a long used apparatus in biochemical laboratories for bacteriology. This was known as the Smith Fermentation Tube, which was an enlarged bulb for the storing of excess bouillon. Its application to water bacteriology allowed for the "determination of gas production by bacteria, for preliminary gas analysis, for the study of reducing powers and for the cultivation of anaerobic organisms in fluid media." (Zinsser 268) The fermentation work also produced one of the key tools (1889) for differentiating colon from typhoid bacilli ‑‑ the former fermented glucose. Later in 1892, Smith documented the value of lactose and saccharose in the classification of the colon‑typhoid group.
In 1891, Smith reported on means of distinguishing two often confused diseases of swine ‑‑ swine plague and hog cholera. The first was due to the Bacillus suisepticus and the second due to a motile bacillus of the paratyphoid B group. Smith, of course, was wrong about hog cholera. Still, Smith and Salmon published two papers in 1886 and 1887 on hog cholera vaccines.
Smith worked another economically important disease of animals in 1895, the "black‑head" in turkeys. Smith studied the problem at the Experiment Station in Kinston RI, and found a parasitic amoeba, which he named Ameoba meleagridis. Some years later, armed with better equipment and seeking to respond to criticism by workers that confused blackhead with coccidiosis, he reconfirmed his findings but changed the name. In 1895, Smith published a general bulletin on "Infectious Diseases of Poultry."
In 1895, Smith accepted the invitation of Walcott of the Mass. Dept. of Public Health, and Eliot of Harvard to come to Boston. In the years that followed, Smith worked on control of water supplies, sewage disposal, typhoid fever from milk, cultivation of anaerobes, indol formation, the adaptation of bacteria to animals, etc. Smith was one of the first bacteriologists to note chemical differences in related or identical bacteria, such as the ability of B. coli to ferment glucose and B. typhosum not. His major studies were devoted to diphtheria and tuberculosis. Smith published some 14 papers on diphtheria during his early years in Boston.
In 1901, Smith was approached by Welch to head the newly created Rockefeller Institute. He declined, felling that the post should go to a person more "intimately connected with the field of medicine as it pertained to man." Smith's work in the 1900's concentrated on discovering the etiological routes for infection, such as the transmission of Sarcocystis muris through feeding (1905).
Smith, with Ernst, issued a report in 1897 on the effectiveness of the tuberculin test in Massachusetts. In fact, he was a strong advocate for milk pasteurization, publically opposing dairymen's claims that pasteurization concealed dirt. Smith argued that bacteria coming from dirt are spore bearers, and are not killed by pasteurization and would therefore continue to be detected.
Smith's interest in tuberculosis began in earnest in 1893, and within a year he was struck by the dissimilarity of the organisms responsible for different types of tuberculosis infections. When he arrived at Harvard, Smith took advantage of the Mass. Cattle Commission's experiments on bovine types. Smith demonstrated in Journal of Experimental Medicine 3 (1898), that while the bovine and human varieties of B. tuberculosis differed in virulence for experimental animals (guinea pigs, pigeons, rabbits), the bovine type was far more severe. Smith also described morphological differences. His work on bovine tuberculosis opposed two misconceptions: the dangerous and widespread public belief that bovine tuberculosis could not be transmitted to man; and Koch's insistence that there was no difference between the bovine organism and that transmitted from man to man. By 1901, Smith’s extensive data convinced Koch.
Interestingly, by 1902, Smith was backing away from an absolute distinction between bovine and human types. "...the bovine bacillus present certain traits which serve to distinguish it from the great majority of bacilli isolated from the human subject. These traits or characters are not the exclusive property of the bovine bacillus..." (Zinsser 277) Also during 1902, Smith directed studies conducted under the Direction of the Div. of Animal Pathology of the BAI, to determine the frequency of tubercle bacilli in dairy products, including butter and cheese.
At the 1903 SAB meeting, Smith was president, and delivered a paper, not listed on the program, on "Further Distinctions between the Human and Bovine Tubercle Bacilli," which was discussed by Park.
The article on thermal death points was a turning point, for he suggested that the scalding layer of milk in most pasteurizers increased the survival of tubercle bacilli. When pasteurization was carried out in a closed container, the organism was killed at 140 degrees after 15 to 20 minutes, instead of 160 for 40.
In 1915, Smith and Brown studied streptococcus from sore throats in five Massachusetts cities and found that these types would not produce inflammations when inoculated into cows udders. They concluded that septic sore throats were not likely to be caused by infected milk.
Always interested in the shared bacterial diseases of man and animals. In 1934, in a essay reprinted in Microbiology in New Jersey: Origins and Developments by Waksman, Starkey and Donovick, Smith suggests that there are two lines of research in pathogenic microbiology, one "trying to dig beneath the observations toward more fundamental concepts embodied in physics and chemistry, and the medical or practical striving towards the surface to bring research into use...The knowledge of the function of microorganisms has had to fight its way to recognition step by step..." (p. 31) For Smith, fundamental research in pathology would investigate the relationship between pathogen and the body. This knowledge would aid in the prevention of disease even after infection. He strove throughout his career to forge a general theory of parasitism, with the understanding that pathogens often adapt to their hosts.
Interestingly, Smith was the first to suggest that a mixture of diphtheria toxin and anti‑toxin might be used for immunization, a method not developed until Behring’s report of 1912. Smith's paper in 1909 was directed at describing the most efficient manner to induce immunity in horses used for antitoxin production.
Smith took directorship of the Division of Animal and Plant Pathology at Princeton in 1914. Most of the early work was on Smith's previous research projects, such as blackhead in turkeys (caused by a protozoan), Vibrio foetus (causing infectious abortion in sheep), and paratyphoid in hogs.
Zinsser has an interesting assessment of Smith's part in the service role of bacteriology: "...he took problems as they were spread out before him by questions crying to be solved....he was never a pure research worker but held position in which the currents of his activities were to some extent directed by specific duties which had to be performed and from which his problems took origin." (Zinsser 283‑284)
Beeson provides a nice list of Smith's major scientific accomplishments, including: the fermentation tube; use of gas production to differentiate between the typhoid bacillus and coliforms; studies on indol formation; the determination of the thermal lability of tubercle bacilli in milk; differentiation between human and bovine forms of tubercle bacilli; discovered a second etiological agent in bovine abortion, Vibrio fetus; use of toxin and anti‑toxin mixtures in immunization; observed intracellular localization of Brucella organisms, and described the porcine type; and devised an increased CO2 atmosphere apparatus for culturing Brucella. (Beeson 1976, 111‑113)