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spores arrive at maturity, which then present themselves 

 like so many dusty particles congregated round a central 

 nucleus. Being so minute, the slightest touch, or the 

 gentlest breath of air, is sufficient to scatter them in 

 thousands, and thus they increase with amazing rapidity. 

 The trivial names of blue, green, and yellow mould, it 

 may be remarked, are of no specific significance, as all 

 these colours are common to the species in the different 

 genera, and occur even in the same species in various 

 stages of its growth. In fact, it is by their different 

 fructification under the microscope alone that the differ- 

 ent genera can be recognised, as their mycelium or spawn 

 is precisely similar, and to the naked eye the appearance 

 they present on the different substances which they 

 affect is identical. 



Though generically and specifically distinct, as we have 

 thus seen, yet, for the sake of convenience, adopting the 

 popular notion and considering them all as one plant, we 

 find that this mould is not only universally distributed, 

 where fungi are at all capable of growing, but that it is 

 also remarkably indifferent as to its selection of habitats, 

 assuming different appearances in different situations, some 

 of which are exceedingly puzzling to the botanist. Usually 

 mould is found on pots of jam, on decaying succulent fruits, 

 on bread when kept too long in a warm and damp situa- 

 tion, on clothes and other articles of common wear; but it 

 is sometimes found in strangely different situations, where 

 it presents the most incongruous forms. The fungi which 

 are produced on animal tissues, more especially in certain 

 diseased conditions of the skin or the mucous membranes, 

 and the presence of which, in such cases, seems to cause 



