68 THE GENETIC AND 



they contain, the formation of crystals, and so forth. 

 But not for the world must anything be taught as to 

 the evolution of this globe ; for this rests from begin- 

 ning to end on unproved hypotheses, for even to the 

 present day the Plutonic and Neptunic theories are 

 disputing the field, and to this day we know not as to 

 many of the most important rocks, whether they ori- 

 ginated by the agency of fire or of water. The new 

 and remarkable discoveries of the great Challenger- 

 expedition threaten to subvert a great many geological 

 notions which had long been regarded as certain. 

 Then again, as to fossils. Who can prove with any 

 certainty that these petrifactions are in truth the 

 fossilised remains of extinct organisms ? They may 

 be as many distinguished naturalists of even the last 

 century maintained marvellous sports of nature, mys- 

 terious "Lusus naturse," or mere rough, inorganic models 

 of the labouring Creator into which He subsequently 

 " breathed the breath of life ; " or perhaps " stone- 

 flesh "(caro fossilis) brought into existence, on the dead 

 rocks by the " fertilising air " (aura seminalis), and so 

 forth. 



But I am wrong ! for with regard to petrifactions, 

 Virchow is in the highest degree speculative, and 

 accepts without any hesitation the rash hypothesis 

 that fossils are actually the remains of extinct or- 



