266 Early Studies in Bacterial Plant Diseases 



Canaletto never saw diviner hues 



Of silver, crimson, gold upon his blues, 

 Nor any other painter after storm! 



Singing and shouting, beside myself with joy, 

 I walked the fields alone in the twilight warm, 



All else forgot, and was again a boy. 



Sometime during 1894 Smith obtained diseased cotton samples 

 identical with those described by Atkinson and determined to 

 investigate still further the question of soil parasitism. In 1895 

 a similarly caused cabbage disease reported from New York, and 

 found also in Maryland, stimulated him to renewed effort. Sweet 

 potatoes sent from Iowa to Washington disclosed a Fusarium 

 " plugging the vascular system," and Halsted worked on the same 

 or a similar disease in New Jersey.*'* Smith learned, likely from 

 Swingle, Rolfs, or Webber, of a tomato disease in Florida, also 

 due to a Fusarium, which practically put an end to tomato growing 

 in some places for early northern markets. During the period 

 1894-1899, Smith obtained more than 500 melon plant infections, 

 and in more than 400 of these demonstrated the presence of the 

 fungus within the vessels. More will be told of these researches 

 later. Years were spent in examining the action of three parasites 

 (or one) to solve the extreme puzzle how to place them in a 

 proper order of systemization. For, said he, " when I make cross- 

 inoculations, I cannot get any cross infections that would indicate 

 them to be the same fungus." •"' Some practical rules for the 

 farmer were early deduced. The prime rule was to keep out the 

 fungus and to this end care was recommended in the use of fungus- 

 free tools and appliances. Cattle should be kept from pasturing 

 in fields where soil was infested, thereby preventing spread of the 

 fungi and diseases on the cattle's feet. Good farming practices 

 were many which would aid in eliminating either origin or spread 

 of the infectious agency. Where soils became infested, either 

 complete abandonment of the field for a period of years or crop 

 rotations utilizing plant varieties not susceptible to the diseases 

 were indicated alternatives. It had long been good farming and 

 scientific practice to pull diseased plants and burn them. The 

 method of greatest scientific interest, however, lay in the later 



°* The fungous infestation of agricultural soils in the United States, op. at., 

 19981-19982. 

 ^^dem, 19981. 



