In the second place, what are known as alien contract laborers are prohibited from entering the United States, that is, persons who come under contract already entered into, to perform labor, whether skilled or unskilled. The law excluding this class was enacted in obedience to the demands of the union laborers of the United States, who did not wish to be subjected to competition with foreign laborers specially imported for the purpose. Actors, teachers, lecturers, and members of other professions are exempted from the law, and so are skilled laborers if domestic laborers of like kind are not available in the United States. A third group of excluded classes are Chinese laborers, the immigration of whom was first prohibited in 1882. A law of 1916 provides, with certain exceptions, that no alien shall be admitted unless he can read English or some other language or dialect. A law passed in 1921 limits the number of immigrants who may enter annually from each country, to 3 per cent of the number already in the United States, or a total of about 356,000. There is now a head tax of eight dollars levied upon every immigrant who is admitted. Persons whose steamship passage has been paid by others or who have been otherwise assisted to come are not allowed to enter. When an immigrant has been denied admission by the commissioner of immigration at the port at which he has landed, he may take an appeal to a special board of inquiry. If the decision of this board is against him he may appeal to the United States commissioner-general of immigration, and finally to the secretary of the department of labor. If the final decision is against him, the steamship on which he sailed is required at its own expense to transport him to the port from which he sailed. _Quarantine._--In pursuance of the power to regulate foreign commerce, Congress has enacted a volume of legislation in regard to quarantine and medical inspection of ships and their passengers coming from foreign ports. In most instances inspections are made by the United States consul at the port from which the vessel sails, and a bill of health is furnished the master of the vessel, but in some Asiatic and South American ports regular medical inspectors are stationed. At various ports along the coast, national quarantine stations have been established at which inspections of incoming vessels are made and at which they may be detained if found to have on board persons suffering from dangerous contagious diseases.