72 THE RELATIVITY OF ALL KNOWLEDGE. 



experiences of disturbance among small stationary bodies, 

 accompanying the movement of other bodies among them, 

 and have generalized the relation between such disturbances 

 and such movements, you consider this particular disturb- 

 ance explained, on finding it to present, an instance of the 

 like relation. Suppose you catch the partridge; and, 



wishing to ascertain why it did not escape, examine it, and 

 find at one spot, a slight trace of blood upon its feathers. 

 You now tinder stand as you say, what has disabled the par- 

 tridge. It has been wounded by a sportsman — adds another 

 case to the many cases already seen by you, of birds being 

 killed or injured by the shot discharged at them from fowl- 

 ing-pieces. And in assimilating this case to other such cases, 

 consists your understanding of it. But now, on con- 



sideration, a difficulty suggests itself. Only a single shot 

 has struck the partridge, and that not in a vital place: the 

 wings are uninjured, as are also those muscles which move 

 them; and the creature proves by its struggles that it has 

 abundant strength. Why then, you inquire of yourself, 

 does it not fly? Occasion favouring, you put the question 

 to an anatomist, who furnishes you with a solution. He 

 points out that this solitary shot has passed close to the place 

 at which the nerve supplying the wing-muscles of one side, 

 diverges from the spine; and that a slight injury to this 

 nerve, extending even to the rupture of a few fibres, may, 

 by preventing a perfect co-ordination in the actions of the 

 two wings, destroy the power of flight. You are no longer 

 puzzled. But what has happened? — what has changed 

 your state from one of perplexity to one of comprehension f 

 Simply the disclosure of a class of previously known cases, 

 along with which you can include this case. The connex- 

 ion between lesions of the nervous system and paralysis of 

 limbs has been already many times brought under your no- 

 tice ; and you here find a relation of cause and effect that is 

 essentially similar. 



Let us suppose you are led on to make further inquiries 



