Criminal law is usually regarded, both by students and byteachers of law, as one of the most attractive portions of their work. It has of course a great practical importance; on accountof the large number of our criminal tribunals and, consequently,of the persons who have to take part in their administration. Foryoung practitioners the criminal courts offer the readiest access to professional employment and thus to experience, instructiveif not lucrative, in the practical details of advocacy. And evenpersons who have no professional interest in legal matters are oftenengaged, as jurymen or justices of the peace, and thus find in discharging public duties that a knowledge of the criminal law is of great assistance to them. Again, without any such call either of public duty or of professional activity, any private citizen mayeasily have direct personal cause to realize the value of this kindof knowledge. For our civilization is not yet so perfect that a man can be sure that even the most prudent administration of hisaffairs will save him from having to invoke the protection of thecriminal law, or that even the highest moral rectitude will removeall risk of his having to defend himself against groundless andmalicious criminal accusations. But there are also other causes,less utilitarian than any of these, which nevertheless play a still greater part in giving the criminal portion of our law that specialattractiveness which it unquestionably has, not only for professional students but even for ordinary readers For this branch of study is rendered attractive to all thoughtful men by its direct bearing on the most urgent social difficulties of our time and on2 CRIMINAL LAWthe deepest ethical problems of all times. And almost all men,whether thoughtful or thoughtless, are fascinated by its dramaticcharacter — the vivid and violent nature of the events whichcriminal courts notice and repress, as well as of those by which theyeffect the repression. Forcible interferences with property andliberty, with person and life, are the causes which bring criminallaw into operation; and its operations are themselves directed to the infliction of similar acts of seizure, suffering, and slaughter.The utmost violence which administrators of civil justice havepower to inflict ranks only among the gentlest of those penaltiesby which the criminal courts do their work. Hence of all branchesof legal study there is no other which stirs men's imaginations andsympathies so readily and so deeply.The interest thus aroused tends naturally to facilitate the progress of the student through the difficulties of this subject; and hasdone much to produce the impression, which happily prevails in the minds of most of them, that this branch of their work is peculiarly easy. That impression is erroneous ; though no doubt, thebeginner may acquire such a knowledge of criminal law as suffices for ordinary needs, either of examination or of everyday practice,without having to face so many points of intrinsic difficulty as hewill usually find it necessary to master, whether in fitting himselfto take an examination for admission to the bar, or a degree in law in any of our leading universities. There is one grave, if not indeed insoluble, difficulty whichhas to be faced in studying the law of crime. And this difficulty comes at the very outset of the subject. It is presented in thefundamental problem — What is a Crime f Clearly the criminallaw is concerned with crimes alone, not with illegal acts in general.But how are we to distinguish those breaches of law which are crimes from those which are merely illegal without being criminal ? Many attempts have been made to answer this question, andto propound a general definition of crime which shall distinguishwrongs which are criminal from those which are merely \'civil.\' Moreover, as the distinction between criminal wrongs and privateor civil injuries is not peculiar to England and America where the common law prevails, but is familiar in every civilized country,attempts have naturally been made to look for such a definitionTHE NATURE OF A CRIME 3of crime as will express this difference in a form so general as to beapplicable to all countries in which this world-wide distinctionbetween criminal and civil wrongs prevails.