248 PASTEUR: THE HISTORY OF A MIND 



virus was not carried by the blood into the first drop, 

 thence transferred diluted to the second, third, etc., 

 and was still present in sufficient quantity in the last drop 

 to produce the effect attributed to the bacteridium. 

 Chauveau's experiments had just shown that viruses 

 could undergo great dilution, as much as 1/150 for the 

 vaccine, 1/500 for glanders, which was ranked then, 

 as we have said, with smallpox and cowpox. These 

 cultures of Koch's were neither numerous enough nor 

 made in sufficiently large volumes of liquid to eliminate 

 the influence of the virus from the dilution. Add to 

 that the results of P. Bert, which were still perplexing 

 to the partisans of the new doctrines. 



All these objections appear to us to-day as mere hair- 

 splitting. It is certain that if any one should bring 

 to us now, for any disease whatsoever, such a collection 

 of proofs as those which Davaine and Koch furnished 

 for anthrax, no one would have the least doubt of their 

 significance. Why? Because the ideas of men of 

 research and of the public have orientated in this direc- 

 tion. The weather-vane has turned; but this vane 

 turned only with much difficulty and much squeaking. 

 Davaine and Koch had blown at it in vain with all the 

 power of their lungs, they had succeeded in stirring it but 

 not in changing its position. It was Pasteur who over- 

 came all resistance by putting to rout everything which 

 served as a pretext for immobility and inaction. 



This definite orientation of mind and effort was the 

 more urgent because for 10 years science had struggled 

 with the difficulties and obscurities of the subject and 

 multiplied its labors and discoveries without seeing 

 light burst forth from any side. The ideas of Pasteur 

 on fermentation did not create a stir solely in the 

 study of anthrax; the preoccupation with the role of 

 bacteria in pathology was general. Klebs had found 



