juiyio,i 9 i6 Storage-Rots of Economic Avoids 563 



same strain. The one striking exception to the above statement may 

 be noted in connection with the results obtained with saccharose, lactose, 

 dextrose, and glycerin broth in fermentation tubes. Strain 3624 pro- 

 duced gas (a small amount) in all, while none of the other strains did. 

 Such a difference, however, is not surprising in view of the fact that 

 Harding and Morse (4) found that of the various strains from different 

 sources studied by them some consistently failed to produce gas. 



The writer wishes to emphasize in this connection that he has carefully 

 compared his results with the studies of Jones (5) and Harding and 

 Morse (4) and has frequently consulted Smith's " Bacteria in Relation 

 to Plant Diseases" (8) for methods. Slight differences in cultural char- 

 acteristics have been noted from time to time between the different 

 strains, but these differences appear to be no greater than would natur- 

 ally be expected between strains of the same organism. No attempt 

 has been made to duplicate all the work of Jones or of Harding and 

 Morse with this group of organisms, but merely to carry the work of 

 comparison far enough to be reasonably sure that the writer was work- 

 ing with a strain similar to or identical with B. carotovorus. 



By a series of cross-inoculations it was shown that the organism fur- 

 nished by Dr. Jones would decay dasheens and the organisms from 

 dasheens softrotted raw carrots and turnips. It should be emphasized 

 in this connection that strain 3624 (Jones) was less virulent for dasheens 

 than the strain isolated from dasheen, though it rotted carrots and 

 turnips with ease. , 



INOCULATION EXPERIMENTS 



As a preliminary test, 12 sterile raw blocks in test tubes with a little 

 water added were cut from corms and inoculated on April 1, 191 5, with 

 a 24-hour-old culture (organism 3595) on beef bouillon. In three days 

 there was evidence of decay in some of the tubes, and in 10 days four of 

 the blocks were completely rotted. The checks, six in number, remained 

 sound. The causal organism was recovered in pure culture from two 

 of the blocks. 



On April 19, 191 5, twelve more sterile raw blocks and also six dasheen 

 tubers in moist chambers were inoculated with a 3-day-old culture of 

 beef bouillon by placing a loopful of the broth in a depression of a cut 

 surface. The raw blocks in test tubes were all decayed by April 24. 

 Four of the tubers in moist chambers were well rotted on the same date 

 and the other two but slightly. The causal organism was reisolated 

 from four. Six raw blocks in tubes and three tubers in moist chambers 

 were held as checks. All remained sound. The lack of material pre- 

 vented further work at this time. The work was again taken up in 

 November, the tubers or corms being cut in two and inoculation made on 

 the wounded surface in moist chambers, the surface being kept moist for 



