No. 4.] MODERN POTATO CULTURE. 69 



difference, not enough to be of practical importance. It 

 occurred to us this year that it would be of interest to 

 plant enough potatoes in that piece of land to see whether 

 these spores were still alive. We did not plant much of it, 

 only a few hills, and the crop was clean, — perfectly clean. 

 Still, as I say, I don't consider that wc have proved the 

 point as to how many years scab fungi would live in the 

 ground. But the experiment is an indication that perhaps 

 it is not always quite as long as it has generally been 

 supposed. 



Ex-Governor Hoard. Do you think the sulphur took a 

 longer time to produce such an effect? Do you trace it to 

 the sulphur? 



Professor Brooks. I think not. The sulphur was not 

 used all over the plot, and I think the crop this year was not 

 w here the sulphur had been used. 



Ex-Governor Hoard. What do you ascribe it to? 



Professor Brooks. We don't know what is essential to 

 the vitality of the fungi. We don't believe they will retain 

 their vitality always ; they must die in course of time. 



Ex-Governor Hoard. I have known of some instances 

 where scabby ground has been treated in Wisconsin, during 

 a very severe drought, by simply plowing the ground re- 

 peatedly, plowing it when a cloud of dust would rise, enough 

 to envelop both team and driver, and one instance where it 

 was plowed three times and turned up to the hot sun, and 

 plowed again, where they thought great benefit would ac- 

 crue from that treatment of the soil. 



Professor Brooks. There has been a feeling in the minds 

 of some that if, during the summer, when the hot-houses are 

 not in use, the soil there could be thoroughly dried, the fungi 

 would be destroyed and the crop of the following winter 

 would be free. It has been tested most thoroughly at Am- 

 herst, with results wholly against it. Of course in the 

 houses the soil could be dried very much more than in the 

 open, because it is protected from rain, and it has the hot 

 sun. 



Kx-Governor Hoard. Would it have the actinic effect 

 of tin' sun? 



