THE POTATO. 175 



also far more farinaceous than those stored in cel- 

 lars in the usual manner ; a remark which in a con- 

 siderable degree holds true of those carefully pitted 

 and preserved in the field. General Barnum recom- 

 mends lining the sides of the potato-vaults with fresh 

 turf, the earth side to the roots, and covering them 

 with the same material. This would be an unques- 

 tionable improvement in excluding the air, partially 

 at least, and thereby preserving the root in a good 

 degree of freshness until required for use. 



•There is scarcely any plant cultivated by man less 

 subject to disease than the potato ; though it may 

 not be impossible that longer cultivation, without 

 much care in propagating from seed, may at length 

 break down the original native vigour of the plant, 

 and thus induce disease. Two diseases only are 

 known to which the plant is liable, the scab and the 

 curl, and the last of these may be considered of re- 

 cent origin. Insects rarely produce any serious in- 

 jury either to the tops or the tubers ; though the last 

 are sometimes assailed by the wireworm, when 

 planted in ground much infested by them. Loudon 

 remarks, " that the scab, or ulcerated surface of the 

 tubers, has never been satisfactorily accounted for ; 

 some attributing it to the ammonia of horsedung, 

 others to alkali, and some to the use of coal-ashes. 

 Change of seed and change of ground are the only 

 resources known at pi'esent for this malady." 



But the most fatal disease is the curl, " which is 

 known from the leaves of the stem becoming shriv- 

 elled, when the roots are found in a state of partial 

 decay, and finally turn rotten." — Brit. Hus. Much 

 speculation has existed on the nature and cause of 

 this disease ; it has been supposed to be occasioned 

 by the use of over-ripe tubers as plants ; by the roots 

 of a particular species becoming tired of the soil in 

 which they have long been grown ; many impute it 

 to the attacks of a small insect which adheres to 

 and preys upon the stem, and which may, it is sup- 



