xxxvi.] POTATO DISEASE, II. PASSIVE STATE. 321 



the Bulletin of the Bussy Institution, part iv., refers to deep 

 planting, which is much the same with earthing-up, and 

 writes, p. 336 : " Theoretically, it would appear to be 

 an advantage to plant deep, that the tubers may have less 

 chance for being infected from spores which have fallen 

 from the surface. Practically this does not work well, 

 but potatoes planted near the surface do best. However, 

 the plan tried by some cultivators in England, with 

 apparently good result, of hoeing the earth up over a 

 good part of the tops as soon as the rot appears, is worthy 

 a trial." 



During the last two years Mr. J. L. Jensen, a gentle- 

 man of Copenhagen, has, chiefly through the mediumship 

 of Mr. C. B. Plowright, of King's Lynn, again placed the 

 subject of earthing-up prominently before the agricultural 

 and horticultural public of this country. 



Some of Mr. Jensen's views have been opposed by Mr. 

 William Carruthers, F.K.S., the Keeper of the Depart- 

 ment of Botany at the British Museum ; by Mr. George 

 Murray, also of the British Museum ; and by ourselves, as 

 contrary to fact, and contrary not only to the experience 

 of botanists, but, what is of more importance, to the ex- 

 perience of practical potato-growers and dealers. Person- 

 ally, we advocate, and have always advocated, careful 

 earthing-up ; it agrees with the practice approved by 

 many potato growers. That earthing-up is, however, not 

 esteemed by all seems shown by the fact that neither Dr. 

 Lang's suggestions here, or Professor Farlow's in America, 

 have been generally adopted. 



Mr. Jensen says a high and sharp ridge of earth 

 should be thrown up round the potato plants a little 

 before the disease has appeared in the foliage, or at least 

 at the very first appearance of it. " The usual moulding 

 practised in all countries," writes Mr. Jensen, " is a flat 

 moulding, by which the uppermost tubers are only 

 covered by one or two inches of earth ;" but the Jensen- 

 ian system requires, after a preceding flat moulding, a 

 y 



