On the Diseases of Wheat. 



5 



A single grain of wheat (estimated at less than the tAo" ^ cubic 

 inch) would therefore contain more than 4^000,000 such s])ores ; 

 but it is hardly possible to conjecture how many sporules each 

 spore contains, since they are scarcely distinguishable under very 

 high powers of the microscope, and then appear only as a faint 

 cloud or vapour, whilst they are escaping from the ruptured 

 spores. A reference to Mr. Bauer's plate and account of this 

 fungus, in the ' Penny Magazine' for 1833, p. 1*26, will furnish 

 the inquirer with very accurate details of its structure and pecu- 

 liarities. 



When this disease prevails, it greatly deteriorates the value of 

 the sample ; imparting its disgusting odour to the flour, it makes 

 it less fit for bread ; but I understand that ready purchasers are to 

 be found among the venders of gingerbread, who have discovered 

 that the treacle, and whatever else they mix up with it, effectually 

 disguises the odour of the fungus : if this in itself is really in- 

 noxious, there can be no objection to such a mode of employing 

 the tainted flour ; but some are of opinion that it is to a certain 

 extent deleterious. Although the Bunt-fungus confines its at- 

 tacks to the young seed, it seems to be a condition essential to 

 its propagation, that it should be introduced into the plant during 

 the early stages of its growth, and that its sporules are most readily 

 absorbed by the root during the germination of the seed from which 

 the plant has sprung. It has been clearly proved that wheat- 

 plants may be easily infected and the disease thus propagated, by 

 simply rubbing the seeds before they are sown, with the black 

 powder, or spores, of the fungus. It is also as clearly ascertained, 

 that if seeds thus tainted be thoroughly cleansed, the plants raised 

 from them will not be infected. This fact is now so well estab- 

 lished, that the practice of washing or steeping seed-wheat in cer- 

 tain solutions, almost universally prevails. Upon simply immersing 

 the grain in water, the infected seeds float, and on the water being 

 poured off nothing but the sound ones remain in the vessel. This 

 simple process, however, is never perfectly effective, because, in 

 threshing the wheat, many of the infected grains (smut-balls) are 

 crushed, and the spores are dispersed in the form of a fine powder, 

 which adheres with considerable obstinacy to the surface of the 

 sound grains, by means of an oily or greasy matter found in the 

 fungi. In order to detach them thoroughly, it has been considered 

 useful to add some alkaline ley to the water in which they are 

 washed ; because oil and alkali unite and form a soapy substance, 

 and then the spores will no longer adhere to the surface of the 

 grains of wheat. Lime, possessing alkaline qualities, has been 

 long employed for the purpose. Common potash, and substances 

 containing ammonia, as the liquid portion of stable manure, have 

 also been used. But, as some persons employ brine, sulphate of 



