568 EXPERIMENT STATION EECORD. 



"grain" oi'curs on all kinds of tobacco which have been examined. 

 Microscopic oxaniinations of the l)listors show a dense deposit of ciy-s- 

 talline substance which tests hav(^ shown to be oxalate of lime. This 

 being the case, it might be supposed that the addition of lime to soil 

 would make the "grain" in cured tobacco more prominent, but speci 

 mens taken from different plats showed that there was no relationship 

 apparent between the amount of lime used as fertilizer and that 

 occurring in the leaves. As to Avhether the "grain" is formed during 

 the process of curing or is present in the growing leaves, nothing- 

 definite can be stated as yet. The author believes it probable that- 

 tobacco plants under certain conditions take up greater quantities of 

 lime than thev can utilize and deposit it in the tissues, and that it 

 becomes visible only after the shrinkage in thickness incident to the 

 process of curing. 



Further notes on the pole burn of tobacco, W. C. Sturgis ( Con- 

 encticat State Sta. Rpt. 1899, pt. 3, pp. 265-269). — In the Annual 

 Report of the station for 1891 (E. S. R., 3, p. 773) the pole burn of 

 tobacco was described at some length, and the isolation of a number 

 of bacteria from the surface of leaves, as well as species of Clado- 

 sporium, noted. Recently leaves were collected which showed the 

 beginnings of pole burn, the tissues along the larger veins being of a 

 darker color and extremely tender. These areas w^ere su])jected to 

 examination and 2 series of cultures maintained, one of which developed 

 an Alternaria and a species of yeast, while the other, which had been 

 sterilized, developed a bacillus. From a doubl}^ sterilized leaf were 

 developed in the course of 10 days a large colony of a bacillus of the 

 type of Bacillus stibtilus, and smaller colonies related to B. tnegathe- 

 rmm, and a few small colonies of Micrococcus. 



The author concludes, as far as the organisms associated with the 

 earliest stages of pole burn are concerned, that Alternaria is the only 

 one which occurs in any abundance, and that it occurs onlv on the 

 surface of the leaf and not in the internal tissues. The presence at this 

 time of Alternaria and other organisms not found previously merely 

 indicates that under certain atmospheric conditions any saprophytic 

 fungus which ma}' be ])resent in the curing barn may attack the dead 

 tissues of the leaves and start in them a process of disintegration, 

 which will almost surely be followed by true bacterial decay. 



The remedial measures recommended in the previous report are 

 reaffirmed. 



On fractional fertilization of muskmelons as a preventive of 

 disease, W. ('. Sturgis {Connecticut State Sta. Iipt. 1S99, j^. 3, pp. 

 270-273, dgrti. l).—\n the report of the station for 1898 (E. S. R., 11, 

 p. 754) an account was given of favorable results attending the use of 

 tobacco stems as a mulch for melon vines. An experiment was planned 

 to test the effect of small applications of plant food from time to time 



