150 THE AMERICAN MONTHLY [May, 



Agar agar roll cultures were then made, from the more 

 or less fluid portion ; these gave unsatisfactory results. 

 We then carefully removed with a sterilized scalpel some 

 of the black areas adjoining healthy tissue with a plati- 

 num needle, made cultures in agar plates, and roll tubes. 

 Several forms of bacteria were obtained, and one of these 

 a bacillus producing a whitish growth on the surface of 

 the agar agar, when inoculated into an apparently healthy 

 rutabaga produced rot. This was not, however, a cru- 

 cial test, since the number of inoculations with pure ma- 

 terial was too limited; secondly, the rutabagas in the field 

 may have been afi"ected with the disease. 



From the same source in 1892 and 1893 we obtained a 

 yellow bacillus ; that, too, in the field of 1892, gave some 

 indications of rot. In 1893 we removed to the green- 

 house sixteen rutabagas from a field in which the disease 

 had not appeared. The leaves were cut off, the plants 

 carefully cleaned and washed and planted in pots. Eight 

 plants were inoculated with the rutabaga bacillus and 

 eight remained as checks. The plants were inoculated 

 in the following way : knives were sterilized by passing 

 through a flame, and small areas were cut out. Inocula- 

 tion was then made with a platinum needle from the 

 culture. To prevent the air having access to the plants 

 the cuts were sealed with wax. The plants showed signs 

 of rot in the course of a few days. It made its way along 

 the fibro-vascular bundle, finally involving the whole 

 plant. After these plants had rotted in this way they 

 were removed to the laboratory and then cultures were 

 made from parts of the turnip adjoining unafl'ected por- 

 tions ; cultures were also made from the black zones. 

 From this material we obtained the yellow bacillus. 



DESCRIPTION OF BACILLUS. 



Morphology. — -Bacillus varying somewhat in length, 

 from 1.87"*, 2.25"' to S.-", width uniform .37". Rods round- 



