EXAMPLES OF THE FOUR METHODS. 481 



And, finally, when the poison has been supplied 

 in too small a quantity to destroy life, eschars are 

 produced, that is, certain superficial portions of the 

 tissues are destroyed, which are afterwards thrown off 

 by the reparative process taking place in the healthy 

 parts. 



These three sets of instances admit of being 

 treated according to the Method of Agreement. In 

 all of them the metallic compounds are brought into 

 contact with the substances which compose the 

 human or animal body; and the instances do not 

 seem to agree in any other circumstance. The 

 remaining antecedents are as different, and even 

 opposite, as they could possibly be made ; for in some 

 the animal substances exposed to the action of the 

 poisons are in a state of life, in others only in a state 

 of organization, in others not even in that. And 

 what is the result which follows in all the cases ? 

 The conversion of the animal substance (by combi- 

 nation with the poison) into a chemical compound, 

 held together by so powerful a force as to resist the 

 subsequent action of the ordinary causes of decompo- 

 sition. Now, organic life (the necessary condition of 

 sensitive life) consisting in a continual state of decom- 

 position and recomposition of the different organs and 

 tissues ; whatever incapacitates them for this decom- 

 position destroys life. And thus the proximate cause 

 of the death produced by this description of poisons, 

 is ascertained, as far as the Method of Agreement can 

 ascertain it. 



Let us now bring our conclusion to the test of the Me- 

 thod of Difference. Setting out from the cases already 

 mentioned, in which the antecedent is, the presence of 

 substances forming with the tissues a compound in- 

 capable of putrefaction (and a fortiori incapable of the 



VOL. i. 2 i 



