FERMENTS, FERMENTATIONS, AND LIFE. 267 



organic matter. Pasteur has thus far met this argument 

 only by the evidence of his experiments which prove that, 

 in contact with purified air, neither fermentations nor putre- 

 factions are possible. That is strictly sufficient, but we can 

 go further. It is by no means a sure conclusion that these 

 germs do not exist, because many of them are invisible 

 under the lens. To begin with, we do note with certainty 

 a certain number of species in atmospheric dust. It is 

 therefore an admissible presumption that, if the remaining 

 ones elude our eyes and our microscopes, that merely proves 

 them to be smaller than the observed ones. But, perhaps, 

 the problem ought to be viewed in a different way. We 

 believe that these visible germs are the exceptions, that is, 

 that they are beings already arrived at a certain degree of 

 development, and that, in reality, all true germs are of 

 dimensions forever beyond the reach of microscopic obser- 

 vation, even conceiving lenses to be immensely more pow- 

 erful than they now are. The microscope barely brings 

 within our range of vision points that measure at least a 

 ten thousandth part of a milli metre. The primitive germs 

 of life cannot even approach the hundred thousandth part 

 of a millimetre. Physics and metaphysics both assure us 

 that we must here give up the hope of measuring and 

 estimating things according to the powers of our limited 

 senses. An effort is needed to pursue with the mind's eye 

 these perpetually-dwindling dimensions, still to go on 

 though the imagination fails in the task, and to realize at 

 last how far removed are the bounds of the microcosm. If 

 the faculty of reaching out beyond the limits of our nature> 

 which is one of the noblest prerogatives of our intelligence, 

 does not desert us, we attain to the idea of the vital monads 

 of Leibnitz, the organic molecules of Buffon, the compre- 

 hension of existence for primal organisms diffused through- 

 out the world by myriads of myriads, and the conception 

 of the infinitely minute within the infinitely minute. 



