186 BOARD OP AGRICULTURE. [Jan., 



pliur would be an advantage in regard to the potato rot. The 

 speaker has said that the fungus which produces the potato 

 rot belongs in the same group with the grape fungus. That 

 being the case, I should think that sulphur might be beneficial. 

 I made an experiment last summer and thought I was bene- 

 fited by the use of sulphur. 



Mr. Halsted. I think you will find sulphur to be of ser- 

 vice in destroying the potato rot fungus. I may be misunder- 

 stood in saying that the application of sulphur to the rusted 

 plant, as in the strawberry rust or the wheat rust, would 

 be of no value. I mean, in saving that particular plant. 

 That is the way I understood the question to be put. It 

 might injure the spores, it might even kill them, and in that 

 way it would be a means of preventing the propagation of the 

 trouble the next year and succeeding years, but to save that 

 plant I think would be impossible, or that portion of the 

 plant that is rusted. It is used up. 



Prof. Brewer. As Dr. Halsted was reading his interest- 

 ing paper, I noted down two or three little things, one of 

 which relates to rust-proof varieties. I think that there has 

 been no one direction in which more observation has been 

 expended than in the endeavor to find some variety of each 

 plant which disease would not attack. I may say that so far 

 as the special inquiries on wheat were concerned, I did not 

 push that line of inquiry further in the census schedules to 

 which I have referred than this : I found that in a good many 

 districts a variety would arise which for a year would seem to 

 be almost rust- proof. Everywhere there is a difference in 

 varieties; some are attacked more than others; but in each 

 locality a variety would spring up, or would be brought in, 

 which for a year or so would be almost entirely exempt, but 

 when that variety had been cultivated in that same region 

 three or four years, it would come to be infested the same as 

 the other varieties. Now, this may arise from either one of 

 two causes : it may be that the variety itself changes in that 

 vicinity, or in that district, so as to be more susceptible to the 

 disease, or it may be that the fungus itself undergoes modi- 

 fications. Now, undoubtedly these low orders of vegetation 



