DISCUSSION WITH BASTIAN 119 



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

 Bastian with urine. Gay-Lussac concludes: 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 

 porcelain 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 utility 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 

 controversy 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. 



