OF THE OX. 83 



To these objections we would reply, first, as 

 regards the novelty of opinions expressed, that 

 we have taken up the pen, because we had to 

 write something different from what has already 

 been published in known works, otherwise it 

 would have been our duty to remain silent; 

 and secondly, as regards the inefficacy of inocu- 

 lation, that organic and vital phenomena have 

 their principles and their laws, which are fixed 

 and invincible, from which it is reasonable to 

 deduce consequences and positive rules of 

 conduct, which cannot yield to superannuated 

 opinions or imperfectly executed experiments. 

 To institute experiments indeed under the rigo- 

 rous conditions of a logical and irrefutable de- 

 monstration, is not so easy a matter as may 

 generally be thought. 



For our part, the principles deduced from 

 strict observation are the basis on which we 

 build, and if it so chance that we are baffled in 

 our experiments we vary them indefinitely ; and 

 if still we are deceived in our hopes, we ascribe 

 the miscarriage to our impotence, to inade- 

 quate means, and to the defective instruments 

 which the physical and chemical sciences, still 

 in their cradle as regards organic matter, 

 G 2 



