20 Levi Otto < Ikatz 



remained healthy. After ten days the inoculum was placed about the 

 stems a second time, but again the plants remained healthy. Finally 

 the cabbage strain was placed about the base of some of the seedlings, and 

 all of these damped-off while the checks continued healthy. 



The following June a similar experiment was performed in which twenty- 

 two different strains of the fungus were tested. Twelve cabbage seeds 

 were placed in each pot, and two pots were used for each strain. The 

 strains were obtained as follows: thirteen isolated from as many different 

 lots of potatoes obtained from New York, Minnesota, Maine, Canada, 

 and some unknown sources; two from cabbage seedlings from western 

 New York; one each from peas, peppers, eggplants, tulips, and grass; 

 and two from unknown sources. Inoculations were made when the 

 plants were two inches high. The cabbage, pea, pepper, and eggplant 

 strains produced typical wire-stem lesions. All the others, including 

 the checks, showed slight lesions, but these appeared to be a shriveling 

 at the base rather than injury from fungus attack. When this experiment 

 was performed, the temperature was abnormally high, and the possibility 

 is that the high temperature, inadequate shading, and injudicious watering 

 caused these peculiar atypical lesions. In this experiment the same 

 Maine and Canada strains from potato which gave negative results in the 

 previous experiment again produced no infection. The argument might 

 be advanced that some of the strains were attenuated. While the exact 

 date of isolation for some of them could not be determined, it is known 

 positively that the cabbage, the eggplant, and some of the potato strains 

 were of the same age. 



In December, 1922, this experiment was repeated. As in the previous 

 experiments, the exact length of time that the strains had been grown in 

 culture was not determined, but most of them were of practically the same 

 age. The cabbage strain, and some of the others also, were the same as 

 those used in the preceding experiment. Five pots, each containing more 

 than fifty plants, were used for each strain. The seed was sown in steam- 

 sterilized soil, and the seedlings were inoculated when they were about 

 two inches high. Here again the cabbage, pepper, pea, and eggplant 

 strains produced typical wire-stem lesions, as did also the tomato, the 

 salvia, and another strain of unknown origin (table 7). All of the plants 

 inoculated with the potato and other strains, as well as the checks, re- 

 mained healthy. 



An experiment was then conducted to ascertain whether or not the 

 strains from potato were pathogenic on potato. The soil of each strain 

 from potato of the preceding experiment was mixed with an equal volume 

 of sterilized soil. A tuber, or half of a tuber, of the Bliss Triumph variety, 

 previously treated in a 1-1000 solution of corrosive sublimate for one and 

 one-half hours, was placed in the bottom of each of ten pots, for each 

 strain of the fungus. An additional amount of inoculum on wheat was 



