258 INTRODUCTION TO CRTPTOGAMIC BOTANY. 



cellular origin, their powers of enduring extreme temperatures 

 mthout destruction, &c., are amongst the causes which make 

 certain minds unwilling to admit their propagation after the 

 fashion of other vegetables ; or, at least, if they allow that 

 when once produced they are capable of propagating their 

 species, they do not consider it impossible that, like chemical 

 substances, they may arise from a certain concurrence of fitting 

 elements. The existence, however, of a vital principle in 

 these bodies places them under very different circumstances 

 from chemical compounds, and, till we have some undoubted 

 fact in proof that organisms possessing life can spring from inor- 

 ganic or dead matter, it seems premature to enter into such 

 speculations. There are, indeed, a few difficulties, but these 

 are not such as to require so extreme a solution. That Fungi 

 should spring up everywhere, under fitting conditions, is 

 readily explained by the enormous quantity of fruit which 

 they produce. The dunghill Peziza, sending its sporidia 

 from its hymenium in a steamlike cloud, may convince us 

 of the powers of transmission which these particles possess, 

 and a multitude of equally cogent examples might be 

 adduced. A single Lycoperdon giganteuvi alone produces 

 myriads of seeds. Multitudes of spores find at once a proper 

 nidus, and throw out their mycelium, which, in some cases, 

 may exist for years without producing fruit, and in other 

 instances is essentially perennial, yielding an annual crop 

 for almost an indefinite period ; as essentially perennial, at 

 least, as many an herbaceous plant, which is propagated inde- 

 finitely by means of new roots or bulbs, while the older ones 

 gradually perish. Other spores are wafted about in the air, 

 where they may remain for a greater or less period, till, obey- 

 ing the natural laws of gravity, they descend in some distant 

 regions. The trade winds, for instance, carry spores of Fungi 

 mixed with their dust, which must have travelled thousands 

 of mUes before they are deposited. There is little difficulty, 

 therefore, as regards the ubiquity and imexpected appearance 

 of many species, or the certainty in the case of common kinds 

 of Asjjergillus, Cladosporium, and Penicillium, of their 

 appearance, where particular bodies are exposed to the air. 



