WILT OF CUCURBITS. 241 



bundle contained bacteria (small bacilli) in large numbers. Higher up one or two vessels contained 

 bacilli of much larger size and in smaller numbers. Some of the vessels also contained a branching 

 myceliurn suggestive of Fusarium. The pot stood on a bench where watermelon wilt experiments 

 were carried on previously. 



(80.) Winter Squash var. Hubbard. The blade of a leaf 1.25 inches broad was pricked many 

 times at the apex. Two months after inoculation the vine was brought into the laboratory. All but 

 a few upper leaves were shriveled. The stem was still green and turgid. The latter was examined 

 in three places for bacteria but none were found. 



(81.) Winter Squash var. Hubbard. A leaf 4 inches broad was pricked many times at the apex. 

 No result. Owing to crowding in a small pot only the upper leaves were alive on January 28, and 

 these were dwarfed. The green stem was examined for presence of bacteria, but none were found. 



(82.) Winter Squash var. Hubbard. A leaf 4 inches broad was pricked many times at the apex. 

 February 28 the vine was wholly dried out. No bacteria were present in the vessels or parenchyma 

 of the stem. 



Remarks. — None of the potatoes or tomatoes took the disease and only two of the 

 muskmelons. The squashes proved very resistant. They were in 4-inch pots and grew 

 well for some time after inoculation. No. 79 was not affected at first but seemed to be 

 affected after a long time. On December 20 the squashes were still in 4-inch pots and 

 growing satisfactorily. 



The early maturity of the potatoes undoubtedly resulted from keeping the plants too 

 long in small pots. All the potatoes in the hothouse behaved in the manner described 

 irrespective of whether they were inoculated or not. The tubers were planted in November 

 and the shriveling began in December and on January 14 was apparent on all but two plants. 

 Several examinations showed no bacteria or fungi in the tissues and the plants had not 

 suffered from aphides or red spiders, nor had they been neglected or frosted. They were 

 in 4-inch pots for about a month when they were transferred to 6-inch pots (about January 

 4) to see if this would help them to recover. It did not, however. When repotted most of 

 the vines were over 2 feet high. These facts favor the supposition that the yellowing and 

 shriveling was a natural one, occurring after the plants had performed their life-work, which 

 was hastened by the small size of the pots. 



From this experiment it was evident that the disease could be produced in the musk- 

 melon with bacilli taken from the cucumber, but not with certainty in squashes. 



The temperature in the hothouse the first two weeks after inoculation (December 6 to 

 20) varied from 60° to 90° F. 



Inoculations of December 10, 1894. 



Fifteen plants including 3 hyacinths {Hyacinthus orientalis), 2 Hubbard squashes 

 (Cucurbita sp.), 2 summer crookneck squashes (Cucurbita sp.), i potato, 2 cucumbers, 4 

 tomatoes, and i cantaloupe, were inoculated in the hothouse, with a white wet-shining, 

 sticky, motile bacillus (cucumber-strain) growing on a potato-cyhnder (pure culture No. 5, 

 December 6, from potato-broth No. 2, December 3). The greatest pains was taken to do 

 the work thoroughly. After each plant was thoroughly pricked I went back over the 

 bench and pricked them again. Much material was used in pricking which was done in the 

 afternoon. More than half the bacteria in this culture were motile. The temperature of 

 the hothouse from December 6 to 20 varied from 60° to 90° F. 



(83a, 84, 85.) Hyacinth. These plants had been potted 3 days at the time of inoculation and 

 the green bud had pushed up i to 2 cm. In each 15 or 20 needle pricks were made into the bud, 

 some of them deep. Up to the eighteenth day there was no sign of the blight. 



(86.) Hubbard Squash. At the time of inoculation this vine was about 2 feet high and had 

 6 good leaves. It was very thrifty. About 40 pricks were made on the apex of the blade of the third 

 leaf which was about 5 inches broad. 



Up to February 27 (79 days) the vine showed no trace of the wilt. The stem was then examined 

 in several places but the vessels and parenchyma were free from the bacteria. 



