14 



sometimes ol other grasses, caused by the attacks of a fungus, 

 and is exceedingly poisonous to both men and animals. It is 

 not so likely to occur on well-drained land as on that which is 

 wet. 



Bust is a disease attacking grains and grasses, and occasion- 

 ally other plants, and is found to be caused by the development 

 of minute fungi in the cellular tissue of the floral bracts, or 

 chaff, and the leaves. It weakens the plant, and often renders 

 the grain crop worthless. The growth of different fungi seems 

 to depend largely upon the state of the weather, whether dry, 

 moist, or variable in temperature, and is therefore difficult to 

 control. Something in addition to what has been suggested 

 may be done against these enemies by a judicious rotation of 

 crops ; by the selection of the most suitable varieties of seed ; 

 by improved methods of cultivation ; or by removing from 

 fields, ditches and hedgerows all those plants which support 

 these injurious fungi, and so perpetuate them. 



Another very destructive form of fungus develops in woody 

 fibre, in close, damp places, producing "dry rot." This is so 

 prevalent in some parts of London that wood-work in houses 

 has to be renewed every ten or twelve years. This form of 

 fungus may be checked in its ravages by saturating the wood 

 with some metallic poison, as corrosive sublimate, or chloride 

 of zinc. Fungi likewise often penetrate the wood of fruit and 

 forest trees, beginning where wounds have been made, and 

 gradually causing the death and decay of the entire mass of 

 timber. In many cases, timber apparently sound, cut from 

 dead trees, will be found on examination to be permeated 

 by the mycelium of some fungus which on exposure to 

 air and moisture will develop and destroy its durability. The 

 growth of fungi on fruit which has been bruised or injured by 

 insects, is one of the most common causes of decay. Experi- 

 ment has shown that a sound appje, innoculated with fungus 

 from a decaying one, may be destroyed in three days, and its 

 tissue filled with the cells of the destroyer. The obvious rem- 

 edy is extreme care in sorting, handling and storing the fruit. 



Time would fail us to recount the damages inflicted upon the 

 husbandman, and so upon the race, by these almost invisible, 

 but innumerable and relentless, foes. It must answer our pres- 

 ent purpose to state that every plant is subject to their attacks, 



