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invested with a silver coat, and injures the beauty and 

 the finish of the articles which are subjected to the pro- 

 cess. It is extraordinary that the poisonous nature of 

 the solution does not destroy it ; but it has been often 

 observed that various species of mould luxuriate in solu- 

 tions of arsenic, opium, and other poisonous chemical 

 substances, which would prove instantly fatal to all other 

 plants. 



It is worthy of remark that the destructive effects of 

 all these parasitic fungi may, in most circumstances, be 

 easily neutralized or prevented by a little intelligent 

 forethought, care, and industry ; and providing incentives 

 as they do to the exercise of these qualities, they com- 

 pensate morally in some measure for the physical evils 

 they occasion. Certain conditions are necessary for their 

 development, and it is to obviating and removing these, 

 that the builder and the farmer must look for ex- 

 emption from the destructive vegetable diseases that 

 affect their properties. It has been ascertained, for 

 instance, that rust and blight arise from the over-manur- 

 ing of fields ; the grain gorged with too copious a supply 

 of nutritious juices, being brought into a favourable con- 

 dition for the development of the dormant seeds of fungi 

 which the wind may have wafted to it. The tendency in 

 corn to form these diseases therefore may be destroyed by 

 steeping the seed before sowing in a corrosive solution 

 or in brine ; but the same end may be secured in a dry 

 season, and on a favourable soil, by moderate manuring, 

 or by a free use of saline manures. 



With regard to the mildew in wheat, it has been 

 suggested by Mr. Tycho Wing, as a remedy, to allow no 



