70 The Potato. 



and their stems so regulated that one stem in every case grew 

 outside and entirely uninfluenced by the frame, and tiro inside 

 within the frame; and the two inside were separated from 

 each other by a brick and mortar partition, so that each stem 

 grew in a separate frame ; and these fiames I regulated in 

 such a manner that every alternate frame could not be opened 

 without my sanction. The sets were large, and had merely 

 a bit cut off their end to promote their decay. No manure 

 was used ; the sets grew very well, and were regulated as de- 

 scribed. Their progress was carefully watched. About the 

 25th of July in each year the first symptom of disease was 

 apparent. The frames were now securely fastened, so that no 

 one of them could he opened, and so remained until the last week 

 in Aiif/ust in each year. The stems outside the frame were 

 spouted with water by a syringe with a very fine rose, especial 

 care heinrj taken that the under part of nearly every leaf should be 

 damped each evening. In ten days they were a mass of disease 

 from bottom to top ; v:it.hin the frame there teas not a trace of the 

 disease. About the middle of the last week in August in each 

 year every alternate frame was opened : two in the morning at 

 11 A.M., the time of closing 4 p.m. ; the other two at noon in each 

 day, closing at 9 p.m.: that is just when the dew is falling. 



The result was exactly as had been anticipated ; the two 

 frames closed at 9 p.m. were in three days diseased ; the other 

 two frames closed at 4 p.m. remained without any appearance of 

 the disease until the middle of September, when the frames 

 being drawn up the stems and leaves were freely syringed, and 

 left open for an hour. In a very feio days thet/ were severely 

 affected. The stems and leaves were now carefully examined, 

 and everything having the slightest suspicious appearance was 

 cut out ; these two frames were then carefully and permanently 

 closed. The potato stems immediately made efforts at growth, 

 pusiied out stalks and leaves, which loere not affected by the last of' 

 October, when these experiments finally closed. The four frames 

 above mentioned had remained entirely closed and quite free 

 from any disease until the middle of September, when, a hot 

 clear and calm day being selected, all four were damped with 

 the syringe, and a diseased vine-leaf being placed among the 

 branches of the stems all four frames were closed and remained 

 as before ; no more time being occupied in the operation than 

 was necessary. Having a vinery with four young vines, very 

 healthy, and growing very vigorously, they also were freely 

 syringed, and two branches of affected potato-stalks introduced 

 among the vines ; the house was ( losetl and the air violently 

 agitated ; in little more than a week it was evident that the leaves 

 of the vines and potatoes were diseased in numerous places ; and 



