262 SPONTANEOUS GENERATION OF 



Spencer, Hackel, and others, in the same category 

 with Darwin, as " evolutionists." The four first- 

 named hold the purely speculative opinion of the 

 origin of living from inorganic matter by natural pro- 

 cesses. No such processes can be proved to exist now, 

 nor is there any evidence that they ever did exist, 

 which does not beg the question at issue. Evolution, 

 in such a sense, is therefore a pure speculation, derived 

 from other sources than biology, and has no title to be 

 placed on a level with the legitimate theory of Darwin, 

 who, like a true philosopher, founds his explanation of 

 the origin of species on natural processes, viz., varia- 

 tion, heredity, and natural selection, which do exist as 

 a matter of fact. Where these end, he stops and 

 refers the origin of life itself to the miraculous inter- 

 ference of the Creator, who " breathed the breath of 

 life" into certain primitive stem-forms of beings. 



It is hardly necessary to say that the so-called 

 spontaneous generation of the putrefactive infusoria, 

 which has lately attracted so much attention, may be 

 put in the same category with primeval plasmagony, 

 as indisposing its adherents to admit the strong dis- 

 tinction between albumen and protoplasm. To discuss 

 this would require a volume, so I may merely state 

 that I have followed closely all the published evidence 

 on both sides, and have contributed some original ob- 

 servations. As far as my opinion may have any value, 

 I may state that, as the question stands at present,, the 

 whole, evidence in its favour rests on the appearance 

 of bacteria in solutions which have been exposed to 

 a heat sufficient to kill all visible adult bacteria, while 

 it is assumed that any presumed invisible germs of 



