70 On the Blight or Mildew of Wheoi. 



obliged to be cleared by the first of August, crops havebeern 

 known to be cut " as green as grass," and to be carried off 

 and spread upon grass land to dry. Yet the grain has been 

 found to mature, and always to afford a fine-skinned beau- 

 tiful sample. Ravgrass that is cut even while in blossom, 

 is well known to mature its seeds with the sap that is lodged 

 in the stems. Hence there is nothing to fear from cuttmg 

 wheat or other corn before the straw be ripe. 



1805. April. That the operation of this disease is car- 

 ried on by the fungus tribe, evidently appears from the 

 ingenious and persevering labours of botanists*. But 

 fungi, it is equally evident, are an effect, not the cmise of 

 the disease. They are the vermin of the more perfect ve- 

 getables; and fasten on them, whether in a dead or in a, 

 diseased state ; but seldom, I believe, while they are in full 

 health and vigour. Their minute and volatile seeds may be 

 said to be every where present — ready to produce their kind 

 wherever they may find a genial matrix. Such at least apt 

 pears to be the nature of the fungus, or fungi, of wheat; 

 for it may be liable to the attack of more than one species. 

 In a dry v.arm summer, which is well known to be favour- 

 able to the health, vigour, and productiveness of the wheat 

 crop, the seeds of fungi are harmless, so long as the fine 

 Aveather contmues. On the contrary, in a cold wet season, 

 which gives languor and weakness to the wheat plants, few 

 crops escape entirely their destructive effects. A standing 

 crop not unfrequently escapes, while plots that arc lodged 

 in the same field, especially in pits and hollow places, be- 

 come liable to their attack. And by the facts above stated, 

 we plainly see, that even strong healthy crops may, in a 

 few days, or perhaps in a few hours, be rendered liable to 

 be assailed — not progressively, as by an infectious disease, 

 but at once, as by a blast or blight. In the state of the 

 atmosphere we arc to look for the cause of the disease in a 

 standing crop ; and nothing is so likely to bring on the 

 fatal predisposition of the plants as a succession of cold 

 rains while the grain is forming. The coolness necessarily 

 gives a check to the rich saccharine juices which arc then 

 rising towards the ear; and the moisture may, at the same 

 time, assist the seeds of the fungi to germinate and take 

 root. Thus reason and facts concur in pointing out the 

 cause and the operation of the diseaset- The natural event 



is 



• As they are set forth in a paper just puhlislicd by Sir Joseph Banks. 

 •f 1 here appear to be reasons whv cora which happens tt) be struck ■Nvith 

 this disease in a dry warm summer is exposed to excessive injury, as facts 



pretty 



