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usually called causes and effects, according as they precedeor follow each other. The sick man does not refuse the re-medy offered by his physician, though neither of them canexplain the peculiar nature either of the disease or remedy,or the manner in which the latter operates in curing theformer.
There is another species of smut which frequently prevailson wheat, quite different from that already mentioned, andwhich is seldom described by authors on husbandry. In theformer or smut-ball, the disease is entirely confined within apellicle or parchment coat, occupying the places of the grains inthe ear, and has the appearance of a small parasitical lycoper-don or puff-ball , occupying and usurping the place of theseeds or grains of the wheat. In this other species the wholeform of the grain is entirely obliterated, and nothing remainsexcept a few irregular fibres of the husk or chaff; the blackpowder being altogether external, and divested of any enve-lop or skin. This disease exactly resembles the blacknesswhich frequently infects crops of barley and oats, and is ob-vious and complete whenever the ears burst from the sheathor shoot-blade. It does very little harm, only destroying suchears as it infects, and these are seldom numerous, and it doesnot spread, neither does it at all injure the sample, as it is en-tirely blown away in the process of threshing and dressing.In 1807, the Reporter observed a good deal of this species ofblackness in one of his fields of wheat. Just at the time whenthe grain was forming, and the flower going off, he tried thefollowing experiment to endeavour to ascertain whether thedisease was infectious. Lie pulled a number of these blackenedears, with which he rubbed a tuft of wheat growing on a bareor missed part of the field, so as effectually to dirty the wholeears of that tuft which was carefully marked. At harvest,the ears of that tuft were entirely free from smut *. Perhaps
* Berwickshire Report, p. 232.