THE POTATO DISEASE. 355 



the crop ; and the second is that to which we have already 

 alluded, namely, not to apply the fresh manure to the land 

 immediately before the planting, but to apply it in the 

 autumn, allowing it to lie in the soil all the winter. Of 

 the plans proposed for treating the potato itself, the best 

 seems to be that in which it is subjected to a high tem- 

 perature. Another plan to prevent the disease appears to 

 be worthy of notice here ; it has been proposed by Mr. Pa- 

 terson of Dundee, who, during the last twenty years, has 

 paid great attention to the disease his theory is that "the 

 only practicable method of combating the disease is to 

 propagate new varieties of plants from the apple." " Mr. 

 Paterson," says a writer in an agricultural paper, "maintains 

 that the potato, as in the case of certain domestic animals, 

 requires cross-breeding, so to speak, in order to fortify its 

 constitution against the influence of the disease : that there 

 is a natural tendency in the plant to degenerate when it is 

 repeatedly grown in the same soil and under like conditions, 

 year after year, without variation ; and that a constant suc- 

 cession of new and healthy varieties should be kept up 



by a judicious selection of roots raised from the apple. 

 ***** 



Believing his theory for the prevention of the potato 

 disease to be the correct one, Mr. Paterson has laboured 

 during the last 17 years to put it to a practical test by 

 raising numerous varieties of plants from the apples. The 

 process has necessarily been a slow one, involving consi- 

 derable labour and expense, but the results obtained are 

 such as must ultimately compensate him for his expendi- 

 ture of trouble and money in carrying out his experiments. 

 He has succeeded in raising a great many varieties of seed- 

 ling potatoes, some of which are so prolific, and of such. 

 excellence in form and quality of tuber, as to warrant the 

 belief that they are destined, when more widely known, to 

 supersede most other varieties now in existence. At pre- 

 sent the kinds most extensively cultivated for commercial 

 purposes are 'Regents' and 'Rocks' (the latter having 

 been introduced several years ago, mainly, we believe, 



