1922] 



ROSEN — A BACTERIAL DISEASE OF FOXTAIL 337 



XIII shows that this halo-disease formed at least a part of the 

 phenomenon under consideration." She states further (p. 168), 

 that "Manns' descriptions of individual lesions are so meager 



and his descriptions of general signs so inclusive as to lead to 



grave doubt about his having worked with a single bacterial dis- 

 ease." This statement is somewhat different from the one made 

 by Miss Elliott in a previous publication (I, '18). In this she 

 says, "The characteristic halo lesions of this disease have been 

 definitely observed in Wisconsin during each of the past five 

 years and are similar to those figured by Manns (PI. XIII) in 

 his Ohio bulletin of 1909. The results of the writer's work on 



halo blight of oats agree with those reported by Jones, Johnson, 



and Redely* ('17) in that typical halo lesions are readily pro- 

 duced by a white bacterial pathogen alone." In view of the 

 facts that Manns had included a number of grasses as hosts and 

 that Jones and his associates had accepted Pseudomonas Avenae 

 as the pathogen I made the following statement in a preliminary 

 note on the foxtail disease: "The effect on oats is not unlike 

 the halo blight recently described by Miss Elliott and it is likely 

 that the organism under discussion is the same as Manns' Pseudo- 

 monas Avenae. However the identity of the organism is still 

 in doubt and the work is being continued." 



The writer is now in a position to say that Manns' descrip- 

 tion of P. Avenae is quite at variance with the account of the 

 foxtail organism which will be presented later. It must be 

 borne in mind, however, that bacteriological methods and de- 

 scriptions in 1909 were not as well developed as they have be- 

 come in more recent years, and when, for example, endospores are 

 recorded in 1909 it must not be assumed that this is an established 

 fact ; the same thing may be said for a large number of cultural 

 reactions. However, while the foxtail organism may be present 

 in Ohio, Manns' description as well as Miss Elliott's, even when 

 interpreted very broadly, clearly indicates a difference in the or- 

 ganism. A comparison of group numbers, using the 1907 chart 

 of the American Bacteriological Society, shows at a glance the 

 marked difference between the foxtail organism and P. Avenae. 

 Manns' group number (I, '09, p. 133) is 111.2223032, while the 

 group number of the foxtail organism is 212.3333013. Among 

 other differences it may be noted that the foxtail organism does 

 not liquefy gelatin, produces no acid, even in the presence of car- 



*These writers considered Manns' Pseudomonas Avenae as the causal organism. 



