DURATION OF VARIETIES OF PLANTS. 



to premiums, as one of my letters from him testifies, and doubtless no man was better 

 aware of the injurious effects of an excess of food and other influences on plants- Then 

 consider the attention which he obviously paid to the culture of the potato, the unusual 

 care and diligence with which he conducted all his inquiries, and the anxious desire he 

 ever manifested to arrive at the truth, by repeatedly trying experiments from which he 

 suspected results unfavorable to the conclusions at which he had arrived. The object, 

 moreover, which he constantly had in view, was utility. To be useful to his country and 

 fellow men, by discovering important truths in cultivation, was the aim of all his inqui- 

 ries. Yet, with such qualifications as these, and when near the close of his invaluable 

 labors, and after fiftj^ years, at least, of experiments and observations on plants, Mr. 

 IvNi'iHT said, " I have, in several instances, tried to renovate the vigor of old and excel- 

 lent nearly expended varieties of the potato, by change of soil and mode, of culture, but 

 I never in any degree, succeeded; all became iniproductive and worthless." Yet, not- 

 withstanding, Mr. Knight, with his profound knowledge of the laws of vegetable life, 

 and his great skill as a cultivator, was foiled in his repeated endeavors to re-invigorate old 

 varieties of the potato; the peasantry of England were seriously told, that to think of re- 

 novating the potato crop, by raising new varieties from seed, Avas a dream, and that if they 

 would only adopt certain methods, they might restore old varieties to health and vigor, 

 and so continue them healthy and vigorous forever. 



The failure of Mr. Knight and others, to restore old varieties of the potato to health, 

 is not the only ground for doubting the efficacy of the means recommended by Dr. Lind- 

 LEY. If the feebleness of the constitution, or the wearing out of varieties were a conse- 

 quence chiefly of their being grown in too rich land, or frequently repeated on the same 

 land, surely garden varieties should have been short lived, and most subject to disease, 

 for gardens generally are much more highly manured than fields, and there the crop is 

 most frequently repeated. But early varieties seem upon the whole, to have been more 

 free from disease than late, or field varieties, and I am inclined to believe that as a general 

 rule, they continue in a healthy and useful condition for a much greater length of time, 

 owing to the non-production of blossoms and seeds. These do not, moreover, have the 

 same high forming in other countries as in England, of late years; and in England, what 

 may be called high farming, is even now the exception, and not the rule. Much of the 

 arable land in the first settled parts of the United States, is well known to have been con- 

 siderably exhausted by taking repeated white crops, without making any adequate return 

 to the soil, in the shape of manure, yet the blight of the potato has been fully as virulent 

 in the United States as in England. In this section of the country, the potato has been 

 grown on land first broken up two or three years ago, and to which, in many instances, 

 no manure has been applied, but the crops are blighted, our plants are now nearly desti- 

 tute of foliage, and in many cases a very considerable proportion of the tubers has alrea- 

 dy decayed. 



Varieties of the ranunculus and anemone, which are propagated by their tubers, are 

 also exempt from many of the causes which Dr. Lindley says must be avoided in the 

 future cultivation of the potato, with a view to restore it to health. The tubers of these 

 plants are not gathered into heaps, and suffered to heat during winter; they are not al- 

 lowed to grow before planting in spring; consequently no useless sprouts are rubbed off; 

 they are not planted on raw manure, nor are they cut into sets; therefore there is no loss 

 of sap, or danger of injury from external causes arising from that practice. Yet, not 

 landing these disadvantages, and notwithstanding the care and skill bestowed 

 b}' the ardent florists, varieties of these plants unquestionably degenerate and wear 



