But though the founders of the system which lies at the basis of the rulesnow regulating the concerns of states inter se were not the first to describethe Law of Nature and the Law of NationsJus NatureJus Gentiumas themost admirablethe most dignified portion of Roman Lawthey speak of itwith a precision and a confidence which were altogether newThey look uponit as perfectly determinable if the proper tests be appliedpartly on theauthority of express texts of Roman Lawpartly by a process of inferencefrom a great mass of recorded precedentsIts fitness for international purposesthey regard as a discovery of their ownand some writers of their day speakof the system as the new scienceNo more doubt of its reality seems to havebeen entertained than (let us sayof the English common law by an Englishmediaeval lawyerIt is sometimes difficult to be quite sure how Grotiusand his successors distinguished rules of the Law of Nature from religiousrules prescribed by inspired writersBut that they did draw a distinctionis plainGrotius's famous workthe 'De Jure Belli et Pacis,is in greatpart composed of examples supplied by the language and conduct of heathenstatesmengeneralsand sovereignswhom he could not have supposed to knowanything of inspired teachingIf we assume him to have believed that themost humane and virtuous of the acts and opinions which he quotes were promptedby an instinct derived from a happier state of the human racewhen it wasstill more directly shaped and guided by Divine authoritywe should probablyhave got as near his conception as possibleAs time has gone onsome partsof this basis of thought have proved to be no longer tenableGrotius greatlyoverrated the extent of recorded history andstill morethe accuracy ofthe recordThe very conception from which he startedthe conception ofa real and determinable Law of Naturehas not resisted the application ofmodern criticismTo each successive inquirerthe actual childhood of thehuman race looks less and less like the picture which the jurists of theseventeenth century formed of itIt was excessively inhuman in warandit was before all things enamoured of legal technicality in peaceBut neverthelessthe system founded on an imaginary reconstruction of it more and more calmedthe fury of angry belligerencyand supplied a framework to which more advancedprinciples of humanity and convenience easily adjusted themselves.
The effects of the 'De Jure Belli et Pacis,both in respect of its generalinfluence and of the detailed propositions which it laid downwere exceedinglyprompt and have proved extremely durableAt about the middle of his reignLouis XIV of France adopted two measures by which he was thought to havecarried the severity of war to the furthest pointHe devastated the Palatinate,expressly directing his officers to carry fire and sword into every cornerof the provinceand he issued a notice to the Dutchwith whom he was atwarthatas soon as the melting of the ice opened the canalshe wouldgrant no more quarter to his Dutch enemiesThe devastation of the Palatinatehas become a proverb of savageness with all historiansthough fifty yearsearlier it might at most have been passed as a measure of severityor mighteven have been defendedbut the proclamation to the Dutch called forth aburst of execration from all Europeand the threat to refuse quarter wasnot acted uponThe book of Grotius was making itself feltand the successorsof Grotius assure us that it was his authority which deterred the Frenchking and the French generals from the threatened outrage.
But there is other evidence of the respect paid to the details of hissystemAmong the most interesting legal products of our day are the Manualsof the usages of war which a great number of civilised states are now issuingto their officers in the fieldThe Manual prepared for the United Statesis the oldest of thembut most of them have followed the attempt to forma Code of Land War which was made at the Conference at Brussels in 1874,an attempt which miscarried principally through recollections of the courseof the great Franco-German war in 1870-1871There is very much that is remarkablein all this private codificationas I propose to show in one or two lectureswhich will followbut perhaps the most singular feature of the Manuals isthe number of rules adopted in them which have been literally borrowed fromthe 'De Jure Belli et Pacis,and specially from its third bookRememberingwhat Grotius himself says of the condition in which he found the law andusage of war when be began to write of itand recalling what we learn fromhistorical sources of the wars of succession and the wars of religionwemay well believe Vattelthe Swiss Jurista contemporary of the Seven Years' War and of Frederick the Greatwhen he tells us that what struck him mostin the wars of his day was their extreme gentlenessand of the standardof gentleness proper to be followed in war Vattel was a severe judge.
I here conclude this Introductory Lecturebut there still remain somepoints of principle which meet us on the threshold of International Law,and which cannot be dismissed absolutely in silenceIn my next lecture Ipropose to consider the binding force of International Lawand with it aquestion of some gravity on which the judges of England and the legal authoritiesof the United States do not entertain absolutely identical opinionsandI will state the way in which I venture to think the various shades of differencecan be got overIn the succeeding lectures I shall have to consider a fewfundamental topics in the system before usand I hope afterwards to givea sketchwhich must be brief on account of the narrow limits of my course,on the law of war by sea and landand finally I will endeavour to dischargea part of the duty imposed on me by DrWhewell's directionsand to statewhat measures proposed in our day seem to me to tend to diminish the evilsof war and to do something towards extinguishing it among nations.
