6 WARFARE IN THE HUMAN BODY 



ledge seems inadequate even for his day, and perhaps shows 

 signs that the facts, or supposed facts, were found for him 

 by assistants, and never properly considered. Whether this 

 is true or not, he did suggest that we might not only work 

 forward from the economy of the animal to the social 

 organism, but that, in selected cases, analogies drawn from 

 the body politic might sometimes be used to elucidate 

 physiological problems. He says : " Hints may be ex- 

 pected if nothing more. And thus we venture to think 

 that the Inductive Method, usually employed alone by 

 most physiologists, may not only derive important assist- 

 ance from the Deductive Method, but may further be 

 supplemented by the Sociological Method." He does not 

 seem to have suggested elsewhere that much more than 

 hints were to be looked for, or that the method might be 

 employed not only in physiology, but also in biology and 

 pathology. In no place can I find it said that it might 

 prove of assistance in discovering how general principles 

 worked in any science whatsoever, if each problem were 

 worked backwards and forwards from one science to 

 another. 



There is no need to go deeply into the question of ana- 

 logical reasoning. It is sufficient to point out that, used 

 with caution, it is the most rapidly fruitful form of all 

 ratiocination. Maine called it, " in the study of juris- 

 prudence, the most valuable of instruments," even when he 

 uttered a caution against its premature employment. 

 For any useful analogy must show sufficient points of com- 

 mon likeness between two sets of observed facts to suggest 

 that a general law rules in both. A true analogy is not 

 merely a fanciful likeness, such as may be made out of one 

 point. Although Mill wrote : " There is no analogy, however 

 faint, which may not be of the utmost value in suggesting 



