116 PASTEUR : THE HISTORY OF A MIND 



in reality convinced that there are germs in all water, 

 even in that which has been carefully distilled, when it 

 is collected in receptacles which have been washed with 

 water containing germs. This fact had already been 

 established by Burdon Sanderson, but the French sa- 

 vants expanded it to a remarkable degree, and stated 

 it more precisely. They also recognized that only the 

 waters from deep sources, those which had undergone 

 in the soil a slow and long filtration through capillary 

 spaces, reached the surface without bringing back the 

 germs which they contained in abundance when they 

 penetrated the soil. They were filtered. We find 

 there all the ideas which have been so useful to us later 

 on the subject of the distribution of germs in water, 

 and out of which was evolved for purposes of steriliza- 

 tion, the Chamberland filter, which has been of such 

 great hygienic value. 



Nevertheless, this explanation did not explain every- 

 thing, and it happened sometimes that when the potash 

 solution had been thoroughly sterilized, or even replaced 

 by an equivalent fragment of potash heated to redness, 

 nevertheless the urine, sterile up to that time, became 

 populated. It is then the urine which supplies the 

 germs: they had not been destroyed by the boiling to 

 which it had been subjected, and thus was introduced 

 into science this very fertile idea that germs could exist 

 in a living state in a nutrient liquid and not develop. 

 Behold the contribution of Bastian! Where Pasteur 

 saw nothing develop, he said: "There is nothing;" 

 Bastian entered the field and said: ''Without your 

 knowing it, there is something of which you prevent the 

 evolution." Pasteur retraced his steps and admitted: 

 it is true! but this something is a germ, and if it remains 

 inert, it is because in all living species the first steps in 

 life are the most difficult to make. 



