Dorothy M. Caylby 473 



host plant the general movement is slow, with an occasional swiftly 

 moving rod. 



Group nu?nber. The group number of this organism, according to 

 the Description Chart of the Society of American Bacteriologists is : 



Ps. 121-2323033. 



So far as is known to the author, this organism has not been previously 

 described, and has therefore been named Pseudomonas seminum,. 



Inoculation Experiments. 



Inoculation experiments were carried out in the open, but little 

 stress can be laid upon the results, as the disease was so prevalent 

 throughout the experimental plots. Pea plants grown in boxes in soil 

 partially sterilized by heat and inoculated just above the ground when 

 the plants were one foot high, showed no disease, whereas in the open 

 seven out of ten inoculations in the stem below the youngest leaf were 

 successful. These contradictory results were probably due to the part 

 of the plant inoculated. The stems of the plants in the boxes had 

 probably matured sufficiently to enable them to withstand the spread 

 of the organism. 



Other outdoor experiments were tried in which the young unfolded 

 leaves were pressed apart near the growing point, the young stem 

 pricked with a sterile needle, a drop of sterile water containing a pure 

 culture of the organism placed on the wounded stem, and the young 

 leaves replaced over the drop. These inoculations also gave definite 

 results in so far as the growth was partially arrested, the leaves turned 

 yellowish, and the upper part of the plants showed the general 

 symptoms of the disease. However, in this case also, some of the 

 control plants treated in the same way with sterile water only, de- 

 veloped the disease. Further attempts were made to grow pea plants 

 under sterile conditions in sand in carboys and watered with nutrient 

 salt solutions, but unfortunately the cultures did not remain sterile 

 owing to the necessity of opening the carboys for manipulation. The 

 seeds for these experiments were sterilized with 1 per cent, corrosive 

 subhmate for twenty minutes, washed twice in sterile water and then 

 placed singly in sterile petri dishes to germinate. After germination 

 the testa was removed, the cotyledons of the seeds were forced apart 

 with sterile instruments to see if the internal tissues were healthy, 

 and those showing any blemishes on any part of the seed were rejected. 

 When the first leaves had unfolded, the peas were planted in the 



