THE PAGE OF NATURE. 



235 



they burst their way through the cell, and are trans- 

 ferred to the water, there to perform their circle of being, 

 and to give birth to new granules. All this takes place 

 with such amazing rapidity, that one hour or two suf- 

 fices for the complete development and escape of the 

 spores ; so that we need not wonder when we are told 

 that, once established, the Achyla prolifera will often 

 complete the destruction of a healthy gold-fish in less 

 than twelve hours." 



The most protean of all the fungi, both in appearance 

 and choice of growing-place, is the group to which the 

 common familiar name of mould has been given. There 

 are no less than three different genera and numerous 

 species included under this one name. There is the 

 white or blue mould, forming the genus Aspergillus 

 (Fig. 29), from the resemblance of its fructification to 



the aspergillus or brush used 

 for sprinkling holy water 

 in Eoman Catholic coun- 

 tries, which is of frequent 

 occurrence on decaying sub- 

 stances of all kinds, and 

 gives a white and downy, 

 or a blue-grey and powdery 



FIG. 29. ASPERGILLUS GLAUCUS. aspect to the objects OH 



which it grows. There is next the green mould, forming 

 the genus Penicillium (Fig. 30), extremely common on 

 all sorts of decaying bodies, and presenting a close resem- 

 blance in appearance to the former genus, with this 

 difference, that its spore -bearing stem divides into 

 numerous branches like a miniature tree, bearing spores 



