202 LOUIS PASTEUR. 



a microscope, had had this sheep's blood under their 

 eyes. Pasteur contented himself with replying that his 

 assertion rested upon a principle, and that he was per- 

 fectly able, without having seen the blood of the sheep, 

 to affirm that under the conditions in which it had 

 been collected that blood was septic. A public corre- 

 spondence ensued, but no understanding could be 

 come to. Pasteur then offered to go himself to Turin, 

 in order to demonstrate upon as many bodies of sheep 

 dead of splenic fever as they would like to give him, 

 that the blood of these dead bodies at the end of 

 twenty-four hours if in the month of March, and in 

 twelve or fifteen hours if in the month of June, would 

 be found to be both splenic and septic. Pasteur also 

 proposed, by appropriate cultures, to withdraw at 

 pleasure the splenic fever poison or the septic poison, 

 or the two together, at the choice of the Italians. The 

 Italians, however, shrank from Pasteur's proposal to pay 

 them a visit in order to convince them of their error. 

 The clearness and certainty of Pasteur's assertions 

 are celebrated, but what gives such authority to all 

 that he advances is, as M. Paul Bert once said, that 

 Pasteur's boldness of assertion is only equalled by 

 his diffidence when he has not experiment to back 

 him up. He never fights except on ground with 

 which he has made himself familiar, but then he 

 fights with such resolution, and sometimes with such 

 impetuosity, that one might say to his adversary, who- 



