We have too little theory in the law rather than too much, especially on this final branch of study.  When I was speaking of history, I mentioned larceny as an example to show how the law suffered from not having embodied in a clear form a rule which will accomplish its manifest purpose.  In that case the trouble was due to the survival of forms coming from a time when a more limited purpose was entertained.  Let me now give an example to show the practical importance, for the decision of actual cases, of understanding the reasons of the law, by taking an example from rules which, so far as I know, never have been explained or theorized about in any adequate way.  I refer to statutes of limitation and the law of prescription.  The end of such rules is obvious, but what is the justification for depriving a man of his rights, a pure evil as far as it goes, in consequence of the lapse of time?  Sometimes the loss of evidence is referred to, but that is a secondary matter.  Sometimes the desirability of peace, but why is peace more desirable after twenty years than before?  It is increasingly likely to come without the aid of legislation.  Sometimes it is said that, if a man neglects to enforce his rights, he cannot complain if, after a while, the law follows his example.  Now if this is all that can be said about it, you probably will decide a case I am going to put, for the plaintiff; if you take the view which I shall suggest, you possibly will decide it for the defendant.  A man is sued for trespass upon land, and justifies under a right of way.  He proves that he has used the way openly and adversely for twenty years, but it turns out that the plaintiff had granted a license to a person whom he reasonably supposed to be the defendant’s agent, although not so in fact, and therefore had assumed that the use of the way was permissive, in which case no right would be gained.  Has the defendant gained a right or not?  If his gaining it stands on the fault and neglect of the landowner in the ordinary sense, as seems commonly to be supposed, there has been no such neglect, and the right of way has not been acquired.  But if I were the defendant’s counsel, I should suggest that the foundation of the acquisition of rights by lapse of time is to be looked for in the position of the person who gains them, not in that of the loser.  Sir Henry Maine has made it fashionable to connect the archaic notion of property with prescription.  But the connection is further back than the first recorded history.  It is in the nature of man’s mind.  A thing which you have enjoyed and used as your own for a long time, whether property or an opinion, takes root in your being and cannot be torn away without your resenting the act and trying to defend yourself, however you came by it.  The law can ask no better justification than the deepest instincts of man.  It is only by way of reply to the suggestion that you are disappointing the former owner, that you refer to his neglect having