DISCUSSION WITH BASTIAN 119 



the must of grape, by Pouchet with hay-infusion, by 

 Bastian with urine. Gay-Lussac conckides: it is the 

 oxygen which has vivified the dead matter; Pouchet and 

 Bastian say: it is spontaneous generation. Then comes 

 Pasteur, who first said: "Not at all; it is germs." Then, 

 when he had been shown that he was deceived: ''It is the 

 cooperation of the germs and of the oxygen." The germs 

 always played a part, and in that respect he won his case. 



Finally, these germs, so resistant, so widespread, 

 present in all waters, stick to the walls of the receptacles 

 washed with these waters, by a mechanism analogous 

 to that which fixes them in the capillary tubes of a por- 

 celain filter. There they dry, and once dried, they are 

 still more resistant. The heating to 120 C. of a flask 

 half full of liquid may sterilize only the moistened part, 

 allowing life to persist in the regions which are not in 

 contact with the liquid. In order to destroy everything, 

 it is necessary to subject the dry walls to 180 C. Hence 

 the utihty of flaming all the receptacles used in micro- 

 biology, and behold once more a practice arising like the 

 autoclave, from the laboratory of Pasteur, and which, 

 along with it, established a good technique and made the 

 future secure. 



Thus it was that, little by little, knowledge extended 

 and became more exact, and that all the objections to the 

 germ-theory ended in giving us more exact ideas on the 

 subject of the evolution, the distribution, and the char- 

 acteristics of germs. From this point of view, one may 

 say that all these discussions have been useful because 

 they have given rise to new experiments. The contro- 

 versy with Bastian was the most useful because there 

 the two adversaries without being of equal force had the 

 same creed and the same faith. Bastian rendered a 

 service to science; he lashed it on its weak side, but he 

 compelled it to advance. 



