BLACK ROT OF THE POTATO: TECHNIC 



265 



with certainty from European potatoes, and its existence did 

 not account for all of our own potato rots, and particularly for 

 those common in the more northern parts of the United States 

 in which the distribution of Bacterium solancearum remained 

 (and still remains) unknown, although it was isolated by us 

 nearly every year from various species of plants received from 

 our Southern States. 



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Fig. 202. — Potato tuber showing lenticel infections due to Bacillus melan- 

 ogenes. At the bottom on the left side and in the center, various infections have 

 fused. From a plunge inoculation by the writer in 1912. 



Following the appearance of Appel's paper, his organism 

 was found in the United States by the writer and others (Morse, 

 Jones, etc.), and two or three similar organisms were soon 

 described, e.g., Bacillus solanisapi'us Harrison. Morse has 

 substituted van Hall's name, Bacillus atrosepticus, for Appel's 

 name but a careful re-reading of van Hall's Dutch paper (Ma}^ 



