[Footnote 46: A blockade instituted by a State against such portions of its own territory as are in revolt is not a blockade for the purpose of settling international differences. It has, therefore, in itself nothing to do with the Law of Nations, but is a matter of internal police. I cannot, therefore, agree with Holland, who, in his _Studies in International Law_, p. 138, treats it as a pacific blockade _sensu generali_. Of course, necessity of self-preservation only can justify a State that has blockaded one of its own ports in preventing the egress and ingress of _foreign_ vessels. And the question might arise whether compensation ought not to be paid for losses sustained by foreign vessels so detained.] [Footnote 47: See above, § 35.] [Footnote 48: This blockade, although ostensibly a war blockade for the purpose of preventing the ingress of foreign vessels, was nevertheless essentially a pacific blockade. See Holland, in _The Law Quarterly Review_, XIX. (1903), p. 133; Parliamentary Papers, Venezuela, No. 1 (Venezuela), Correspondence respecting the Affairs of Venezuela.] [Sidenote: Admissibility of Pacific Blockade.] § 45. No unanimity exists among international lawyers with regard to the question whether or not pacific blockades are admissible according to the principles of the Law of Nations. There is no doubt that the theory of the Law of Nations forbids the seizure and sequestration of vessels other than those of the blockaded State caught in an attempt to break a pacific blockade. For even those writers who maintain the admissibility of pacific blockade assert that vessels of third States cannot be seized. What is controverted is the question whether according to International Law the coast of a State may be blockaded at all in time of peace. From the first recorded instance to the last, several writers[49] of authority have negatived the question. On the other hand, many writers have answered the question in the affirmative, differing among themselves regarding the one point only whether or not vessels sailing under the flag of third States could be prevented from entering or leaving pacifically blockaded ports. The Institute of International Law in 1887 carefully studied, and at its meeting in Heidelberg discussed, the question, and finally voted a declaration[50] in favour of the admissibility of pacific blockades. Thus the most influential body of theorists has approved what had been established before by practice. There ought to be no doubt that the numerous cases of pacific blockade which have occurred during the nineteenth century have, through tacit consent of the members of the Family of Nations, established the admissibility of pacific blockades for the settlement of political as well as of legal international differences. [Footnote 49: The leader of these writers is Hautefeuille, _Des Droits et des Devoirs des Nations Neutres_ (2nd ed. 1858, pp. 272-288).] [Footnote 50: See _Annuaire_, IX. (1887), pp. 275-301.]