=Commercial Treaties.=—From time to time the United States has established, by treaty, commercial relations with other countries. These treaties are made for the mutual advantage of both parties. They usually provide that citizens of each country may carry on trade with one another subject to the established tariffs, and that there shall be no governmental discrimination against such trade.[167] They allow each country to maintain consuls in the territory of the other. On a few occasions the United States has concluded reciprocity treaties providing for reciprocal free trade, in whole or in part, with other countries. An arrangement of this sort was made with Canada in 1854 but was brought to an end twelve years later. =The Consular Service.=—Commerce with foreign countries is assisted and facilitated by the consular service. The United States maintains consuls in all important foreign countries and these countries, in turn, send their consuls here. There are several classes of officials in the consular service; the more important are consuls-general, consuls, and consular agents. Consuls-general are stationed at the larger foreign ports and exercise a general supervision over consuls in their respective districts. Consuls and consular agents are maintained in less important foreign centers of trade. [Sidenote: How consuls are appointed.] All members of the American consular service are appointed by the President, but since 1906 the selections have been made by competitive examinations for the lower grades and by promotion for the higher. [Sidenote: Their duties.] Members of the consular service gather information concerning trade opportunities and send this information to Washington where it is printed and distributed to American merchants and manufacturers. Consuls verify the invoices of goods shipped to the United States so as to avoid delay at the custom house. They assist American citizens who may be traveling abroad, particularly those who go abroad to buy merchandise. In a word they are the sentinels of American foreign commerce. Until 1906 the American consular service was not highly efficient because the appointment of consuls was usually made on political grounds. Men who had rendered service in party politics were often given important consular positions although possessed of no real qualifications for the work which they were expected to do. Moreover, whenever a change of administration took place in Washington many consuls were removed from office and new ones appointed. This injured the service by preventing the development of experienced officials. Since 1906 the situation has greatly improved because appointments and promotions have been made upon a basis of merit alone.