342 Chief of a Laboratory of Plant Pathology 



ter'ium f?ialvacearum EFS covered twenty years (1900-1920). 

 Although the disease had been first described in 1891-1892 by 

 G. F. Atkinson, Smith believed himself to have been " the first 

 to reproduce the disease on leaves and bolls of healthy cotton 

 plants (19OO-I905) with the true parasite isolated from capsule- 

 spots and leaf-spots. He was also the one who proved the stem- 

 blight known as black-arm and the angular leaf-spot to be due 

 to the same organism " (1905),"^ and he showed that " the cotton 

 gummosis of Asia Minor and the leafspot of South Africa are 

 due to it." -^ In 1920, in his text-book. Introduction to Bacterial 

 Diseases of Plants,-'^ was published his most complete account of 

 the disease and its organism, and of the literature on the subject. 



In 1898 Smith arranged that a request for samples of gummed 

 sugar cane be sent by officials of the Department to Australia. 

 At that time cultural materials were not available to him in this 

 country, and several years, therefore, went by before he was able 

 satisfactorily to restudy Cobb's conclusions as to Pseudomonas 

 vascularum, a bacterium parasitic on sugar cane in Australia and 

 elsewhere. In 1903 he obtained his " first clean cut pure culture 

 inoculations . . . and subsequently worked out the cultural charac- 

 ters of the parasite." "^ His 1901 bulletin on the cultural characters 

 of the yellow Pseudomonas group was a carefully prepared, com- 

 parative study and included a designation of this species as well 

 as occasional references to other not closely related species such as 

 Bacillus arnylovorus, B. coli, and B. carotovorus. Indeed, his study 

 of Cobb's disease of sugar cane was started in part to determine 

 whether the " germ " {Pseudomonas stewarti) of Stewart's disease 

 of maize, which he was studying in 1898, is the same organism. 



In 1898, when Smith began to wage his epoch-making contro- 

 versy with Dr. Alfred Fischer as to whether bacterial diseases of 

 plants actually exist, he selected six " genuine plant parasites," the 

 pathogenic nature of which had been established and reaffirmed 

 by subsequent investigation: (l) Bacillus amylovorus, BurriU, 

 Arthur, and Waite; (2) Bacillus oleae, Savastano (1886-1889); 



"We;;z, 314-316. 



^* Synopsis of researches, op. cit., 32. 



I' Op. cit., 314-339. 



"^ Synopsis of researches, op. cit., 28-29. Smith's study of Cobb's disease of sugar 

 cane began in 1901 and lasted until 1914. The cultural materials received were from 

 New South Wales. 



