278 BRITISH HUSBANDRY. [Ch. XXII. 



remedied. It probably arises more from the temperature of the seasons in 

 different years than from any cause which can be controlled by manage- 

 ment ; but we conceive that it may be in some degree guarded against by 

 occasionally changing- the species grown upon tlie soil, and by always 

 paying close attention to the quality of the roots from which the sets are 

 to be cut, and choosing them from those of the most perfect growth. Plants 

 which come up curled should be treated like weeds, and hoed out, which 

 evinces the propriety of retaining more than one eye in every set, so as to 

 allow of cutting them out without creating blanks. 



Independently, however, of the curl, and of every known species of 

 disease, a very extraordinary failure has taken place within the last three 

 years in the crops of potatoes, extending in some places over entire dis- 

 tricts, and in others partially confined to portions of the same field. 

 Various essays have been recently published with a view to ascertain the 

 cause, all written with intelligence, and some assigning facts and inferences 

 which may perhaps at length lead to its discovery, and then, it may be 

 presumed, to its prevention or remedy. Some of them, indeed, appear to 

 carry such weight of evidence that they might almost be assumed to be 

 conclusive did they not vary from each other, and did tliey not all leave in 

 some degree unaccounted for, the singular circumstance of the same land, 

 tilled and manured in the same manner, planted with the same root, and 

 sown and gathered at the same time, still failing in one part and being 

 productive in another, as well as the injury being only of late occurrence. 

 Thus, Mr. Andrews, to whose essay we have already alluded, ascribes it 

 " to our altered systtm of cultivation, in deferring the time of planting to a 

 later period, and taking up the crop in an immature state," 



Messieurs Macdonald, of Huntly, to whom a premium was awarded by 

 the Higldand Society, attribute it "to \\\q heating of the seed ; and to that 

 cause alone :" for, "in April and May of the years 1832 and 1833, in 

 which nearly lialf of their crops failed, the heat of the sun was great, 

 accompanied by frequent showers; which, combined with the common 

 plan of cutting seed-potatoes two or three weeks before planting, and the 

 exudation of the natural sap from the cuts, occasioned the heaps to be 

 heated to such an extent as for the most part to destroy the vegetative 

 principle.'' This, tliey say, was in some measure proved by the circum- 

 stance that " the cuttings taken from the outside of the heaps, having un- 

 dergone little or no heating, produced healthier plants than those taken 

 from the centre*:" and also " that in 14 acres planted in 1834, and put 

 into the ground tlie same day on which the sets were cut, there was no de- 

 ficiency whatever.'' 



But although this may be one cause, it has yet been properly observed 

 by Mr. Towers, " that the potato is extremely susceptible of injury from 

 two very opposite agents — heat and cold f." Thus, on collecting the 

 remains of a fine crop into separate heaps to dry and harden, the thermo- 

 meter fell during the evening to two or three degrees below the freezing 

 point, and although the frost only lasted two or three hours, yet those 

 parcels which had been exposed to it were found in the following March to 

 have the skin soft, the mass pulpy and loose, and resembling the same 

 injury as if it had been scalded. 



Messieurs Walker and Winder, of Liverpool, who obtained the silver 



* Potatoes, the tubers of which were planted whole, were however found to escape 

 better than cuttings : probably, from their bf ing better dtifeadeU by their skiu from the 

 danger of being rotted by the eflects of heating. 



t Quart, Journ. of Agric. N. S.. Ko. xxx. p. :^33. 



