236 LOUIS PASTEUR. 



grossed : he had, what his daughter called, ' the face 

 of an approaching discovery.' 



' Ah ! what a grand thing it would be,' he was 

 heard from time to time to murmur to himself with a 

 suppressed voice, ' if one could arrive at that if the 

 fact that the attenuation of the microbe of fowl 

 cholera proved not to be an isolated one ! ' But if 

 anyone ventured to ask him a timid question as to 

 the phase his experiments were going through, he 

 would reply, ' No, I can tell you nothing. I dare 

 not express aloud what I hope.' 



At last one day he came up from his laboratory 

 with a triumphant face. His joy was such that tears 

 stood in his eyes. I have never seen a more radiant 

 expression of the highest and most generous emotions 

 than emanated from his countenance. 



' I should never console myself,' he said while em- 

 bracing us, ' if a discovery such as my assistants and 

 I have just made w r ere not a French discovery.' 



And with the clearness which is the charm of this 

 powerful mind, he related to us the most recent dis- 

 coveries of his laboratory. 



In neutralised chicken infusion the splenic microbe 

 can no longer be cultivated at a temperature of 44 

 or 45 degrees. Its cultivation, on the contrary, is 

 easy at 42 or 43 degrees ; and in these conditions the 

 microbe produces no spores. At this latter tempera- 



