COMPARISON WITH SIMILAR ORGANISMS. 



39 



several pavtic ulars— i. o., the, calla rot does not. -while the latter does 

 produce gas. The former is not atfeeted by ditlused light, while the 

 latter is affected, etc. The shape of colonies differs. There are, of 

 course, numerous points in which the two organisms agree, but they 

 differ in enough essential points to show that they are not the same. 



Bacillus olenu'cm Harrison."— Cultures of this organism were ob- 

 tiiined, and repeated inoculations were made with fresh cultures into 

 various parts of calla plants. At the same time parallel inoculations 

 were made with similar cultures of the calla-rot germ. In twenty- 

 four hours after inoculation nearly all the plants inoculated wibli the 

 calla germ showed the characteristic symptoms of disease, and the 

 decay continued to progress until the plants 

 were practically destroyed. On the other 

 hand Harrison's organism did not affect the 

 plants in any way, showing that the two 

 organisms are not identical. 



Heinz' s hyacinth germ {Bacillus hyacinthi 

 septiciis).^ — In ord(>r to learn the effect of 

 the calla organism on hyacinths, more than 

 100 hyacinths were inoculated with fresh qx\\- 

 tures of the calla germ. The leava\s, ilower 

 stalk, and flowers were inoculated. Most of 

 the inoculations were made in plants grow- 

 ing in the open when the weather was bright 

 and warm. A few hyacinths were potted 

 and placed in a greenhouse. The flowers 

 were inoculated by dropping a single drop 

 of a 24-hour-old beef -broth culture into the 

 flower. The leaves and flower stalks were in- 

 oculated by scraping a (juantity of the fresh 

 growth of the organism from a slant-agar 

 surface, applying it to the diseased spot, 

 and then puncturing the plant with a sterile 

 needle through the mass of organisms. None of the plants in the open 

 showed any symptoms of the disease whatever, although they were 

 watched daily for more than two weeks. The inoculated plants in the 

 greenhouse did not show an}^ symptoms of disease until the expiration 

 of five days, when a few of the leaves and flower stalks began to 

 soften. The affected parts gradually decayed throughout (fig. 7). 

 Pure cultures of the calla organism were obtained from these diseased 

 parts of the hyacinths. The difficult}^ with which this organism 



« Harrison, F. C. Preliminary Note on a New Organism Producing Rot in Cauli- 

 flower and Allied Plants. Science, n. s., Vol. XVI, .July 25, 1902, p. 152. 



'> Heinz, A. Zur Kenntniss der Rotzkrankheiten der Pflanzen. Centralblatt f. 

 Bakt. u. Parasitenkunde, Bd. V, 1889, p. 535. 



Fig. 7.— Hothouse hyacintB inffott- 

 lated in a flower with the calla 

 organism. 



