Of thh Sciench of Plant Bactfriology 295 



Rurrill in 1800-1801 had published '" Preliminary Notes upon 

 the Rotting of Potatoes " ■*' but, since the " origin of the material 

 [was] not given and the micro-organism [was] not described," 

 Smith was not sure that this disease was the same as the one he 

 studied.-" Halsted, too, during the years 1891-1893 had presented 

 various papers on tomato and potato blights. But, since the dis- 

 tinct disease of the bacterial wilt of cucumbers and cantaloupes 

 appeared confused in these writings and since the results were not 

 based on pure culture experiments and not " very conclusive," "■• 

 Smith, in 1895, using diseased tomato plants sent from Mississippi, 

 began " an extensi\^e series of microscopic examinations, artificial 

 cultures, and plant inoculations ... in the laboratories and green- 

 houses "' of the Department. He isolated Bacillus solanacearum 

 but he accredited Halsted with being first to draw attention to 

 the disease of tomato and potato; and evidently he believed 

 Halsted's " aicumber and muskmeion disease . . . entirely 

 different " from the cucurbit wilt due to Bacillus tracheiphilus. 



In Chapter VI we considered Smith's field studies of 1894 

 in South Carolina. These, continued in 1895 from July until 

 September on James Island and at Monetta, brought forth his 

 discovery that eggplant, as well as tomato and potato, is subject 

 to the bacterial " wilt " or brown rot of Solanaceae. Later, in 

 1908,^' he described the disease from tobacco, and he and other 

 workers would find the malady present in many other kinds of 

 plants. His studies of the organism and the various plant genera 

 affected by it would last until 1920 and extend to Euphorbiaceae 

 (Ricinus), Onagraceae (Fuchsia), Leguminosae (beans and pea- 

 nuts), and Compositae (Helianthus), etc.*^ 



In 1896, furthermore, he successfully infected potato by using 

 the Colorado potato beetle {Doryphora decemlineata^ ^^ as an 

 agent of disease-transmission. Thus, in a greenhouse under care- 

 fully controlled conditions, he arrived for the second time at proof 

 that insects play an important role in spreading maladies. 



** Proc. nth Ann. Meet. Soc. Prom. Agric. Set., 21, 22, 1890; also, An additional 

 note on the rot of potatoes, ibid., 29, 1891. 



*=^ Bull. 12, op. cit., 1. 



"Bull. 12, op. cit., 5, 6. 



*"The Granville Tobacco Wilt, Bull. I4l (11), Bur. of Pi. Indus., U. S. D. A. 



** Synopsis of researches, op. cit., 26-27. 



*• Leptinotarsa decemlineata. See Smith's Intro, to bact. dis. of plants, op. cit., 199. 

 Also, Fifty years of pathology, op. cit., 25. Bull. 12, op. cit., 22-23 for an account 

 of his investigations. 



