It is thought that true cholera did not exist in China until 1669 when it was carried there from India. It is first described from Japan in 1821 although an epidemic which devastated Tokyo in 1718 may have been cholera. A great pandemic of cholera started in India, in 1817, extending over Asia but not invading Europe. The second great pandemic is of importance as being the first to invade Europe. It started in India in 1826 and advancing slowly reached Persia in 1829, going thence by way of Astrakhan to Russia, Sweden, Northern Europe and England. By 1832 it had spread over the whole of Europe. In the same year, 1832, it reached Canada and thence spread to Fort Dearborn where it infected the soldiers who subsequently carried the disease down the Mississippi valley. It was also introduced into New York and spread thence South and West so that by 1836 cholera was present all over the U. S., not disappearing until 1838. It disappeared from Europe in 1839. The next European outbreak or third pandemic lasted from 1846 to 1862 and was traced to India by way of land and sea, that by land following the caravan route by way of Persia and Russia and that by sea from Indian pilgrims going to Mecca and there causing the infection of Mahommedan pilgrims from Egypt and European Turkey. This pandemic reached the U. S. in 1848, starting at New Orleans and going up the Mississippi valley. Central and South America and the West Indies were also invaded by the third pandemic. The fourth great pandemic invaded Europe by the usual routes and continued from 1863 to 1875. During its continuance there were two outbreaks in the U. S., one in 1867 and another in 1873. That in 1873, when it was introduced into three widely separated parts of the country, was the last appearance of cholera in the U. S. The fifth pandemic began in 1883 and affected particularly the Mediterranean seaports of France, Spain and Italy. It was during this epidemic, in 1883, that Koch, working in Egypt, discovered the cause of cholera, the _Spirillum cholerae asiaticae_. A very serious outbreak of cholera, which originated in 1891, in pilgrims from the delta of the Ganges, reached Europe in 1892, almost a million deaths occurring in Russia. It was during this epidemic that cholera appeared in Hamburg and gave opportunity for those careful studies as to transmission of the disease to be later referred to. It is usual to recognize a sixth pandemic which began in 1902 and spread over India, China and the Philippines. This pandemic continuing was a cause of great mortality among the soldiers of the recent Balkan war. During the World War there was much cholera among the Austrian forces in Galicia. It also prevailed in Bulgaria, Greece and Turkey.