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tier adheres to the damp grains, and can only be afterwardsremoved by washing; whereas, in the threshing-machine,the grain being dry, and instantly subjected to several strongblasts of wind, the black powder from the broken balls is allor mostly blown away, and the produce remains clean.
Of the cause of this disease little is known ; but happily thedisease can be prevented by careful pickling, as already men-tioned. In what manner the pickling acts as a preventive of thesmut is also but little known *; but the fact, that wheat, if cleanfair seed be used, and if it is properly pickled, is pot affectedwith smut, even in those years in which that disease most pre-vails, is undoubted. Some farmers, on a mistaken idea thatpickling could be of no use, because the nature of the dis-ease and the mode of operation of this salutary preventivewere both upknown, chose several years ago to neglect pick-ling seed wheat. They afterwards candidly acknowledged,that their wheat crops were considerably deteriorated; whiletheir neighbours, who pickled from experience without theory,comparatively escaped in a season when siput prevailed morethan ordinary f. Facts are all that can in general be knownto science; causes, and modes of ppcration, not being alwayswithin the reach of the human faculties: all that can everbe attained by the most accurate investigation, and by themost truly scientific genius, is a knowledge of the natural se-ries of facts, as following each other in a chain, and which are
• An ingenious account is given in the Farmer ’s Magazine of the probablemodus propagandi of the smut. It is supposed the black powder contains theseeds of a fungus so minute as to be taken into the circulation of the juices of thegrowing wheat; and to rest in the embryo grains in the ear, and there to vege-tate, and living on the matter of the young grain propagates its species. Theapplication of urine and quicklime destroys these seeds if attached to. the grainsof wheat; and if they be not so attached where the wheat is sown, but come af-terwards into contact with it in the soil, which it is found they sometimes do,particularly near woods and hedges, they do not vegetate, unless the wheat besown without pickling.
f Berwickshire Report, p. 220,