78 DISTEMPERS OF CORN. Parti. 



form the moil- confiderable and nioH; uieful part of this work, was 

 for fome years fo much taken up in- eftablilhing the horfe-hoeing 

 hufbandry, that he had not leifure to attend to the diHempers ot 

 wheat, till the great lofo he fuuained in the years 1753 and 1754, 

 by the n/J}, engaged him, not £0 much to inquire into the caufe, 

 as to dilcover a remedy for it. 



He h of opinion, that the powder which forms the nijl is the 

 extravafated juice of the plants : becaufe, as foon as the ri/Ji comes 

 on, the growth of the plant is ftopt, the blade becomes no larger, 

 the ftalks grow no higher, nor the ears any bigger. " The juices, 

 " fays he, ftill rife in the plant : they mull therefore be turned to 

 "' fome other ufe ; and it appears probable to me, that they are 

 " converted into this brown powder, which daily increafes in 

 " quantity as long as the diftemper lails. I cannot think it a fub- 

 " ifance foreign to the plant, brought there by any external means. 



" I have never feen corn llruck with the rujl, but in very dry 

 *' weather, and (which, is of importance to be obferved) never but 

 *' when there has not been the ieaft dew for feveral days. — May 

 " not the want of that moifture, fo friendly to vegetation, dry the 

 " furface of the blades and frems fo as to make them crack, and 

 " the veffels, being broke, pour forth their contents .'' 



" This opinion, continues he, is fupported by an experiment 

 " which I made ; and v/hich likewife teaches us how to flop the 

 " progrefs of this diftemper, when it feizes corn before it fpindles. , 



" On the 6th of July 1753, I planted 159 grains of the wheat 

 ** which I intended to ufe for feed. They did not begin to ipring 

 ** up till the 20th. On the i8th of the fame month,- I fowed 104 

 " grains more. They fprouted foon, and had very large blades of a. 

 " deep green. About the end of Auguft, the blades changed their 

 " colour, and the ri//^ foon appeared. It made an afionilhing 

 " progrefs. The earth, for two feet diftance from the rows, was 

 " covered witli the rufty powder, and towards the rows of the 

 " plants it lay at Ieaft one-twelfth of an inch thick. The blades 

 " were almoft entirely deftroyed, and the lofs of the plants feemed 

 *' to me inevitable. 



" As I was perfuaded that this powder was the extravafated 

 " juices of the plants, I was in hopes that if I could turn the courfe 

 " of the juices from the diftemper'd blades, the plants might pro- 

 " duce new blades and ftalks ; as I obferved that they were perfedtly 

 *' found wherever they were covered by the earth. 



" The 



