GEORGE K. K. LINK 591 



soft rot. Reinke and Berthold' indirectly demonstrated that bacteria obtained from 

 rotting potato tubers would rot tubers in the absence of fungi: Prillieux in 1879' had 

 described the Micrococcus or rose-red disease of wheat; Comes in 1880^ had recog- 

 nized the pathogenic role of bacteria in plant diseases; and Wakker in 1883" had de- 

 scribed the yellow disease of hyacinths, and by infection experiments definitely as- 

 sociated the disease with bacteria. It is generally stated that the work of Burrill 

 (i876-83),s on the nature and cause of fire blight, was the first which conclusively 

 estabhshed that a specific bacterium (Micrococcus amylovorus) causes a specific plant 

 disease. This, however, was not completed until 1885 when Arthur'' grew the organ- 

 ism in pure culture and produced infection with it. 



In the main, however, the botanical profession was so blinded by the luster of 

 De Bary's and other mycologists' successes in estabhshing causal relations between 

 specific plant diseases and definite species of fungi that it failed to consider seriously 

 the possible role of bacteria in plant diseases. Indeed, the consensus was that bacteria 

 could not cause specific diseases of plants. The legume nodules were not considered 

 pathological, and their bacteria were designated as "symbionts." It was contended 

 that if bacteria were at all involved they were secondary to fungi, because bacteria 

 could not enter the stomata of plants, and if they should get access to the tissues 

 through wounds their progress would soon be checked by the plants' development of 

 an excluding layer of cork. 



The credit for overcoming this notion, which was most prevalent in Germany, be- 

 longs notably to Sorauer,^ who in 1886 began to defend the concept that bacteria 

 cause specific plant diseases, but even more to Erwin Smith,* who carried on a spirited 

 polemic with Dr. A. Fischer^ of Berlin during 1897-1901, and convinced the botanical 

 world that certain bacteria cause specific plant diseases. 



Relatively few men have worked intensively in phytobacteriology. Smith not 

 only pioneered the field but contributed a considerable part of the literature. The 



' Reinke, J., and Berthold, G.: Zersctzung der Kartojfel. Berlin, 1879. 



^ Prillieux, Ed. : Maladies des Plantes agricoles el Arbresfniiliers elforesliers catisees par des Para- 

 siles vegetaux. Paris, 1895. 



3 Comes, O.: Criltogamia agraria, Vol. i. Naples, 1891. 



4 Wakker, J. H.: "Vorliiufige Mittheilungen liber Hyacinthenkrankheiten," Bot. Centralhl., 14, 

 315-16. 1883. 



5 Burrill, T. J.: "Pear Blight," Tr. Illinois Slate Hort. Soc, pp. 114-16. 1878; "Fire Blight," 

 ibid., pp. 77-78. 1879; "Anthrax of Fruit Trees," Proc. Am. Assoc. Adv. Sc, 29, 583-97. 1880; Am. 

 Nat., 17, 319- 1883. 



^ Arthur, J. C. : "Proof That Bacteria Are the Direct Cause of the Disease in Trees Known as Pear 

 Blight," Bot. Gaz., 10, 343-45- 1885; "Pear Blight," Neiv York Agr. Exper. Sta., Geneva Kept., 5. 

 1886. 



7 Sorauer, P.: Handbuch der Pjlanzenkrankheiten (2d ed.). Berlin, 1886. 



8 Smith, E. F. : "Are There Bacterial Diseases of Plants? A Consideration of Some Statements in 

 Dr. Alfred Fischer's Vorlesungen iiber Bakterien," Centralbl.f. Bakteriol., Abt. II, 5, 271-78. 1899; 

 "Dr. Alfred Fischer in the Role of Pathologist," ibid., pp. 810-17. 1899; "Entgegnung auf Alfred 

 Fischer's 'Antwort' in betreff der Existenz von durch Bakterien verursachten Pflanzenkrankheiten," 

 ibid., 7, 88-100, 128-39, 190-99. 1901. 



9 Fischer, A.: "Die Bakterienkrankheiten der Pflanzen. Antwort an Herrn Dr. Erwin F. Smith," 

 ibid., 5, 279-87. 1899. 



