present century several severe epidemics of yellow fever occurred in New York and in Philadelphia, and even as far north as Boston. In the great epidemic of 1798 the mortality in Boston was 200; in New York, 2,080; and in Philadelphia, 3,500. The last-named city suffered a series of epidemics about this time—1797 (mortality, 1,300), 1798 (mortality, 3,500), 1799 (mortality, 1,000), 1802 (mortality, 307), 1803 (mortality, 195), 1805 (mortality, 400). The immunity of these cities for many years, notwithstanding their intimate commercial relations with Havana and other infected ports, is in my opinion largely due to sanitary improvements, and especially to the construction of sewers and paving the streets; also to the enforcement of suitable quarantine regulations.
The great epidemics in the United States during the present century occurred in 1853, 1867, 1873, 1878. The epidemic of 1878 was the most disastrous known; 132 towns were invaded, and the mortality was 15,934 (number of cases about 74,000).
In Europe the ravages of yellow fever have been chiefly restricted to Spain and Portugal. This is due to the facts that meteorological conditions are there favorable for the development of the exotic micro-organism to which the disease is due, and that these countries have constant commercial intercourse with infected ports in the West Indies. The first epidemic in Spain occurred in 1700 at Cadiz. This city also suffered in 1730-'31, 1733-'34, 1764, 1780, 1800, 1804, 1810, 1819-'21. The epidemics of 1800, 1810, and 1819 were not limited to the city of Cadiz; the disease extended to the interior, and caused a considerable mortality in the provinces of Granada and Andalusia. In 1878 a limited epidemic occurred for the first time in Madrid. The first Lisbon epidemic was in 1723; the great epidemic in this city was inaugurated in 1856, and reached its acme of development the following year.
Upon the west coast of Africa yellow fever prevails principally along the coast of Sierra Leone. At St. Louis (Senegal) an epidemic occurred in 1778, the first of which we have any knowledge in this vicinity. Frequent epidemics have occurred in Senegambia, and the disease has occasionally prevailed upon the Gold coast, the Congo coast, the Cape Verd Islands, and the Canary Islands. At Nassau in the Bahama Islands yellow fever prevailed as an epidemic in 1861, 1862, 1863, and in 1869.
Another infectious malady which, like yellow fever, has a very restricted endemic prevalence is the disease known as beriberi. This prevails chiefly upon the seacoast of Oriental countries, and upon the islands in proximity to these coasts in the Pacific and Indian Oceans. It has been imported to the West Indies and to Brazil, where it prevails to a limited extent in the coast region.
