331 



should be more and more discredited^ as exact observa- 

 tion gradually drove it to its resting place among those 

 organisms which are minuter and more obscure. The 

 long existence of a belief Avhich was only a shifting 

 supplement to crude and imperfect knowledge, can obviously 

 afford no a pi'iori support to the theory in its modern form in 

 Avhich it is directly linked Avith purely physical views of the 

 nature of life. On the other hand, the very minuteness and 

 obscurity of the organisms among which it is now believed 

 to take place are an argument in its fcivour. If Ave agree Avith 

 Mr. DarAvin that " it does not seem incredible that from some 

 loAv and intermediate form both animals and plants may have 

 been developed/'^ Ave are naturally disposed to speculate as to 

 the origin from the inorganic Avovld of such a form itself. Con- 

 ceiving such a phenomenon once to have taken place, it 

 Avould be difficult to believe that it has not done so again and 

 again, inasmuch as the collocation of conditions Avhich it 

 requires must necessarily have from time to time recurred. 

 Hence, it might reasonably be supposed to be Avithin the 

 range of possible observation, to demonstrate at least some 

 steps in the actual genesis of life, and this is Avhat the advo- 

 cates of spontaneous generation believe themselves to have 

 done. As a proof of its purely pliysical nature, nothing 

 could be more conclusive than the jjcj' saUum experimental 

 development of life from substances absolutely devoid of it, 

 and under purely physical conditions; yet in connection Avitli 

 a theory of universal evolution, this involves as much diffi- 

 culty as the supposition of an absolute limit between the 

 organic and inorganic Avorlds. To affirm that the interval is 

 passed over ^;(?r saltuni Avould not in the least dimmish the 

 discontinuity, because it Avould still imply the existence of 

 an interval ; yet that it is only passed jtjer saltum, is after all 

 the conclusion that must be arriA^ed at from the statements of 

 believers in spontaneous generation. 



A comprehensive theory of evolution Avould fail most 

 signally of comprehensiveness if it refused to give any account 



nutriment and corrupt juices."— ('On Tape and Cystic Worms,' translated 

 by Huxley, p. 8.) 



Origin from ill-digested nutriment Avould have been simply spontaneous 

 generation, for which Professor Huxley has recently proposed the term 

 Abiogenesis ; tlie production of new organisms by modification of the living 

 substance of another is Xcnogciicsis. Mr. Spencer has repudiated Hetero- 

 gcnesis as a synonym of spontaneous generation, and in conformity with his 

 synnnetrical terminology has used it as the correlative of Homogenesis for 

 those cases of multiplication which have been described under the name of 

 alternate generation, and in which there is oidy a cyclical recurrence of the 

 same form. — {' Principles of Biology,' i, p. 210.) 



' ' On the Origin of Species,' 4fh cJ., p. 571. 



