198 TRANSACTIONS OF THE 



8. The comparative cost of cattle food and manure — tiventy sovereigns. 



9, Best essay on agriculture — ten sovereigns. 



All reports, &c,, must be sent to the Secretary, James Hudson, 12 Han- 

 over Square. Contributors will keep copies of their essays, as the Secre- 

 tary cannot be responsible for their return. 



The following extracts are from Part I, of Volume 19, of the Journal 

 of the Royal Agricultural Society of England, just received by the Ameri- 

 can Institute : 



PRIZE ESSAY ON THE POTATO, ITS CULTURE, PRODUC- 

 TION, AND DISEASE. 



By Jeffery Lang, M. D. 



In July, 1845, standing on an eminence on the north-east side of the 

 orchard of four acres, I was surprised at seeing a broad barid of blackened 

 leaves running diagonally across the orchard, bearing the direction of 

 south-west to north-east, and in which band the apple trees looked as if 

 they had been scorched with fire. AVithin the lines of the band there did 

 not appear to be a green leaf; the smell was foetid, and very disgusting. 

 Passing downward by the road fence, to make a closer investigation, I 

 found that the band of blackened leaves was about a thousand feet wide, 

 resolvable into three, like stripes on a ribbon ; of considerable intensity 

 in the middle, shading out at the edges. The leaves on the trees in the 

 band were shrivelled and blackened, but firmly adherent; and, although I 

 did not notice it then, I have since found it to be the fact, that numbers of 

 the lone- shoots were strangely contorted. The grass in the orchard was 

 very high. It was attributed to lightning, as there had been a violent 

 south-west gale, four or five days before. The leaves of the black-thorn, 

 in the hedges, were blackened, like the apple leaves. 



The potatoes in the nursery plot, at the southern end of the orchard, 

 were much discolored ivitkin the line of the band, hit not at all beyond 

 it. We traced this black band fourteen or fifteen miles in a straight line. 

 Every field of potatoes within the line were much shrivelled and cut ; those 

 without, unaffected at the time. In about a fortnight, or three weeks, the 

 disease was almost universal, foetid and offensive. AVhen dug up, the 

 sound ones soon had the disease with increased virulence. The disease 

 had appeared in certain localities before, one or two years ; but in 1845, 

 all accounts agree as to its extent and malignity. 



The opinion that the disease originates in the tuber planted, or in the 

 Stem growing from it, is a delusion. It always originates in the leaf. 



The way the potato is produced from the tuber, has been investigated. 

 Dry, clean potatoes, were placed on a chimney piece, in a seldom used 

 room. They threw up stalks, short, thick, and studded with minute 

 leaves ; while on the summit of the stalk, were three or four larger, but 

 still minute, leaves, forming a tuft. Speedily from the axils of the minute 

 leaves, a shoot was thrown forth, terminating in two leaves, closely en- 

 wrapped, the one by the other. This was the germ of the future potato, 



