William Leishman observes Leishmania donovani in the spleen of a soldier who dies from Dum-Dum fever. Charles Donovan helps to identify the protozoan causing the disease.
Leishman, W. B. 1903. On the possibility of the occurrence of trypanosomiasis in India. Br. Med. J. i: 1252-1254.
Donovan, C. 1903. On the possibility of the occurrence of trypanosomiasis in India. Br. Med. J. ii: 79.
F. G. Novy cultivates trypanosomes isolated in the blood of rats.
Novy, F. G. and W. J. MacNeal. 1903. On the cultivation of Trypanosoma lewisi. Contributions to Medical Research, Ann Arbor: George Wahr. 549-577.
Martinus Beijerinck obtains the first pure culture of sulfur-oxidizing bacterium, Thiobacillus denitrificans. Under anaerobic conditions it uses carbon dioxide as a source of carbon.
Beijerinck, M. 1904. Phenomenes de reduction produits par les microbes. Arch. Neerl. (section 2) 9: 131-157.
Cornelius Johan Koning suggests that fungi play an important role in the decomposition of organic matter and the formation of humus.
Koning, C. J. 1904. Beitrage zur kenntnis des lebens dur humuspilze und der chemischen vorgange bei der humusbildung. Arch. Neerland. Sci. Exact. Et Nat. 9:34-107.
Franz Schardinger isolates aerobic bacilli which produce acetone, ethanol, and acetic acid. These are important industrial chemicals.
Schardinger, F. 1904. Bacillus macerans. Centralblatt f. Backteriologie, II XIV: 772.
Fritz R. Schaudinn and Erich Hoffman identify Treponema pallidum, the cause of syphilis. The bacterium is isolated from fluid leaking from a syphylitic chancre and is spiral in appearance.
Metchnikoff and Syphilis Research during a Decade of Discovery, ASM News 62, 1966. p.307 [pdf]
Schaudinn, F. R. and E. Hoffman. 1905. Uber Spirochatenbefunde in Lymphdrusensaft Syphilitischer. Dtsch. med. Wschr. 31: 711.
Shigetane Ishiwata discovers that the cause of a disease outbreak in silkworms is a new species of bacteria, later called Bacillus thuringiensis, or Bt. Ishiwata called the organism "Sotto-Bacillen." ("Sotto" in Japanese signifies sudden collapse.)
Ishiwata, S. 1905. Concerning "Sotto-Kin" a bacillus of a disease of the silkworm. Rept. Assoc. Seric. Japan. Pp. 160-161.
Sir Roland Biffen shows that the ability of wheat to resist infection with a fungus is genetically inherited.
Biffen, R.H. 1905 Experiments with wheat and barley hybrids, illustrating Mendel's Laws of heredity. J. Roy. Agric. Soc. 65:337-45
August von Wasserman describes the "Wasserman reaction" for the diagnosis of syphilis in monkeys. The test uses complement fixation and becomes the basis for the general uses of complement tests as diagnostics.
Wasserman, A., Neisser, A., and C. Bruck. 1906. Eine serodiagnostische reaktion bei syphilis. Deutsche med. Wchnschr xxxii: 745.
N. L. Sohngen presents groundbreaking work on methane-using and methane-producing bacteria. This is the first proof that methane can serve as an energy and carbon source.
Sohngen, N. L. 1906. Ueber Bakterien, welche Methan als Kohlenstoffnahrung and energiequelle gebrauchen. Zentralbl. Bakteriol. Parasitik. Abt. I. 15: 513-517.
A newly appointed pathologist in the Panama Canal Zone, Samuel Darling, performs an autopsy on a patient with a disease resembling tuberculosis and an agent resembling Leishmania sp. He recognizes significant differences between the etiologic agent and Leishmania sp., and names the organism Histoplasma capsulatum, believing that it is a protozoan. It is now known to be a fungus.
Darling, S. T. 1906. A protozoan general infection producing pseudo tubercules in the lungs and focal necroses in the liver, spleen, and lymph nodes. JAMA. 46: 1283-1285. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.4 [pdf]
Erwin Smith and C.O. Townsend discover that the cause of crown galls is a bacterium called Agrobacterium tumefaciens.
Smith, Erwin, and C.O.1907. Townsend. A plant tumour of bacterial origin. Science 25: 671-673
Howard Ricketts shows that Rocky Mountain spotted fever is caused by an organism that is intermediate in size between an virus and a bacterium. This organism, Rickettsia, is transmitted by ticks. Ricketts dies from typhus, another rickettsial disease, in 1910.
Ricketts, H. 1909. A micro-organism which apparently has a specific relationship to Rocky Mountain spotted fever. J. Am. Med. Soc. 52: 379-380. In Microbiology: A Centenary Perspective, edited by Wolfgang K. Joklik, ASM Press. 1999, p.8 [pdf]
Sigurd Orla-Jensen proposes that physiological characteristics of bacteria are of primary importance in their classification. A primary example is a monograph he later publishes on lactic acid bacteria that establishes the criteria for assignment.
Orla-Jensen, S. 1909. Die Hauptlinien des Naturlichen Bakterien-Systems. Centralblatt fur Bakteriologie. Section 2, XXII: 305-346.
Carlos Chagas discovers the trypanosome, which he named Trypanosoma cruzi, and its mode of transmission, via reduviid bugs, as the cause of the human disease named for him.
Chagas, C. "Ueber eine neue Trypanosomiasis des Menschen." Mem. Inst. Oswaldo Cruz 1:158-218
Charles Henry Nicolle demonstrates that typhus fever is transmitted from person to person by the body louse. This information was used in both world wars to reduce the incidence of typhus. Nicolle is awarded the Noble Prize in Medicine or Physiology in 1928
Nicolle, C. H., C. Compte, and E. Conseil. 1910. Experimental Transmission of Exanthematous Typhus by body lice (Pediculus vestimenti). Ann. Past. Inst. 24: 261-267.
Raimond Sabouraud summarizes about twenty years of his systematic and scientific studies of dermatophytes and dermatophytoses in a classic treatise, Les Teinges. He introduces a medium for the growth of pathogenic fungi.
Sabouraud, R. 1910. Maladies du Cuir Chevelu III. Maladies Cryptogamiques. Les Teinges. Masson et Cie.
Francis Peyton Rous discovers a virus that can cause cancer in chickens by injecting a cell free filtrate of tumors. This is the first experimental proof of an infectious etiologic agent of cancer. In 1909 a farmer brought Rous a hen that had a breast tumor. Rous performed an autopsy, extracted tumor cells and injected them in other hens, where sarcoma developed. Rous is awarded the Noble Prize in Medicine or Physiology in 1966
Rous, Peyton. 1911. Transmission of a malignant growth by means of a cell free filtrate. JAMA. 56: 198.
Rous, Peyton. 1911. A sarcoma of the fowl transmissable by an agent separable from the tumor cells. J. Ex. Med. 13:397-411
Paul Ehrlich announces the discovery of an effective cure (Salvarsan) for syphilis, the first specific chemotherapeutic agent for a bacterial disease. Ehrlich was a researcher in Koch's lab, where he worked on immunology. In 1906 he became head of the Research Institute for Chemotherapy. He sought an arsenic derivative. The 606th compound worked. He brought news of the treatment to London, where Fleming became one of the few physicians to administer it.
Ehrlich, P. 1912. Ueber Laboratoriumsversuche und klinische Erprobung von Heilstoffen. Chem. Ztg. 36: 637-638.
The first discovery of bacteriophage, by Frederick Twort. Twort's discovery was something of an accident. He had spent several years growing viruses and noticed that the bacteria infecting his plates became transparent.
Twort, F. 1915. An investigation on the nature of ultra-microscopic viruses. Lancet, 2: 1241-1243.
Chaim Weizmann, using the knowledge of Pasteur's discovery that yeast ferments sugar, uses Clostridium acetobutylicum to produce acetone and butyl alcohol. These were essential to the British munitions program during World War I.
Weizmann, C. 1915. British patent, 845.
McCrady establishes a quantitative approach for analyzing water samples for coliforms using the most probable number, multiple-tube fermentation test. The test is based on the ability of coliforms to grow in selective broth at 35=F8C producing acid or gas within 24 to 48 hours. The number of coliforms and the 95% confidence limit can be determined using MPN tables for the volumes and number of fermentation tubes used
McCrady, M.H. "The Numerical Interpretation of Fermentation Tube Results." J. Infect. Dis. 17:183
Felix d'Herrelle independently describes bacterial viruses and coins the name "bacteriophage."
Felix d'Herrelle: His Life and Work and the Foundation of a Bacteriophage Reference Center, ASM News 48, 1982. p.297 [pdf]
D'Herrelle, F. 1917. Sur un microbe invisible antagoniste des bacilles dysenteriques. Comp. rend. Acad. Sci. 165: 373-375.In Milestones in Microbiology: 1556 to 1940, translated and edited by Thomas D. Brock, ASM Press. 1998, p157 [pdf]
J. N. Currie discovers how to produce citric acid in large quantities from the mold Aspergillus niger-by employing a growth limiting medium rich in iron.
Currie, J. N. 1917. The citric acid fermentation of Asperigillus niger. J. Bio. Chem. 31: 15-37.