ON THE CURL IN POTATOES. 325 



another channel, and to throw back into the tubers that 

 portion of the vital principle of the plant, which would 

 have been exhausted in the formation of flowers and seeds. 

 Nothing will more contribute to prevent degeneracy in the 

 potato, and especially to prevent curl, than this treatment. 



In proof of what I have already advanced on this sub. Experiments 

 ject, I shall now state a few experiments made by myself in y l e author ' 

 the years 1801,-2,-3. They appear to me to be quite con- 

 clusive, and will go farther to convince, than a volume 

 written without experiments. 



In the autumn of 1800, when in Fife, at a friend's house, 

 I met with a potato of the long flat kind *, which I thought 

 very excellent, and obtained a few to cultivate for my own 

 use : he however informed me, that they had been so in- 

 fested with the curl for some years, that he had resolved to 

 abandon the culture of them altogether. This led me to 

 conclude, that, from their shape, &c , they were well 

 adapted for being made the subject of some experiments I 

 had previously resolved to make, with a view te ascertain 

 the truth of the new idea, upon the cause of the curl, 

 which had been some time before mentioned to me. Ac- 

 cordingly, I selected about half a peck (14lb.) of these, 

 as near the size and shape of the annexed sketch as possi- 

 ble. I took one or two sets from each end of each potato, Sets taken 



that is, from the extreme, or dry end, and from the um- froi71 ^ e °PP°* 



J site ends of po- 



bilical, or wet end, next the connecting radicle: each sort tatoes. 



was planted upon the same ground, but in different rows, 

 with the same kind and quantity of manure to each, and in 

 every respect in exactly the same circumstances, on the 

 27th of April, 1801. 



The season was very favourable. Upon examining the Result;, 

 plants about the end of June, I found, that all those that 

 ■were taken from the wet, or least ripened end of the po- 

 tato, had come up, and were looking well and healthy, ex- 

 cept three plants, which were a little affected with the dis- 

 ease : these I threw out, preserving only such as were quite 

 free from it. Upon examining those plants, which were 



* A sketch of a tuber of this kind, of the natural size, accom- 

 panies this, showing the different cuts or sets, &c. 



produced 



