Florida and Calhorma Laboratorils 261 



stain the germs in CLiciimbcr but also leave the tissues faintly- 

 stained, too. Tiic more important extensions and improvements or 

 plant bacteriological technique made in connection with research 

 on this disease were commenced, however, the following autumn 

 and winter, after Smith had spent a summer studying, and had 

 presented a paper before the August meeting at Brooklyn, New 

 York, of Section G of the American Association for the Advance- 

 ment of Science on, " The Watermelon Disease of the South," " 

 caused by a fungus which he provisionally named " Fusarium 

 niveum." 



Smith himself can best describe his accomplishments in this, 

 another and next line of researches, which culminated in a still 

 more important address, " The Fungous Infestation of Agricul- 

 tural Soils in the United States,"'' read August 25, 1899, at the 

 Ohio State University before the Botanical Section of the Associa- 

 tion. During a period of sixteen years (1894-1910), together with 

 his epoch-making laboratory investigations of bacterial diseases of 

 plants. Smith devoted himself " to the study of the Fusarium 

 diseases of plants, a subject which was then very new. There 

 were," he has written," 



at this time in the United States a number of destructive diseases of 

 unknown origin, particularly on staple crops in the Southern States, in 

 which I found Fusaria constantly and suspiciously present. I studied and 

 made experiments with the Fusaria present in diseased melons, cotton, 

 cowpeas, potatoes, tomatoes, and cabbage. I isolated the fungus from the 

 interior of these plants in pure cultures derived usually from single conidia 

 and with it produced the disease abundantly in case of several of them, 

 thus showing it to be the parasite. I proved infections from the soil; 

 inability of the various isolations to cross-inoculate, e. g., on soil infected 

 with pure cultures of the melon fungus I grew, from seed, rows of water- 

 melons containing many plants, every one of which contracted the disease, 

 alternating with rows of tomatoes, none of which contracted the disease 

 although they were in the infected soil and only a few inches away from 

 the dying melons; showed that the melon Fusarium was still infectious 

 after being held dr}' in culture tubes for three years, and in case of the 

 cabbage disease that the organism causing it remained alive and able to 

 infect in soil from a diseased field which had been kept dry in the 

 laboratory for two years. 



attacked by Bacillus trachetphilus. . . ." Smith's memorandum shows the date of 

 this as May 5, 1894. 



" Proceedings, 43rd Meeting, 289-290, pub. March 1895. 



'" Scientific American Supplement, no. 1246: 19981-19982, Nov. 18, 1899. 



^■'Synopsis of researches of Erwin F. Smith, op. at., 20-21. 



