EXAMPLES OF THE EXPLANATION OF LAWS. 567 



similar chemical action in other matter in contact 

 with it. But while the investigation thus aptly 

 exhibits the second mode of the resolution of a com- 

 plex law, it no less happily exemplifies the third; the 

 subsumption of special laws under a more general 

 law, by gathering them up into one more comprehen- 

 sive expression which includes them all. For the 

 curious fact of the contagious nature of chemical 

 action was only raised into a law of all chemical action 

 by these very investigations ; just as the Newtonian 

 attraction was only recognised as a law of all matter 

 when it was found to explain the phenomena of terres- 

 trial gravity. Previously to Liebig's investigations, 

 the property in question had only been observed in a 

 few special cases of chemical action; but when his 

 deductive reasonings had established that innumerable 

 effects produced upon weak compounds, by substances 

 none of whose known peculiarities would account for 

 their having such a power, might be explained by con- 

 sidering the supposed special property to exist in all 

 those cases, these numerous generalizations on sepa- 

 rate substances were brought together into one law of 

 chemical action in general : the peculiarities of the 

 various substances being, in fact, eliminated, just as 

 the Newtonian deduction eliminated from the in- 

 stances of terrestrial gravity the circumstance of 

 proximity to the earth. 



2. Another of Liebig's speculations, which, if it 

 should ultimately be found to agree with all the facts 

 of the extremely complicated phenomenon to which it 

 relates, will constitute one of the finest examples of 

 the Deductive Method upon record, is his theory of 

 respiration. 



The facts of respiration, or in other words the 



