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in Europe until after the discovery of America, it has been epidemic many times in the United States, in places ranging from Pensacola to Boston. An excellent account of the last epidemic, which occurred in New Orleans, in 1905, has been written by Sir Hubert Boyce, the Dean of the Liverpool School.

Three expeditions have been sent from Liverpool to study yellow fever, and all the members of both expeditions to Brazil were stricken with the disease. Dr. Walter Meyer, a member of the first expedition, and a young man of great promise, died of the fever. One of the members of the second expedition had a severe attack of the disease, followed by disagreeable and disfiguring complications. His misfortunes did not end Here; for, during convalescence, the river boat on which he was being carried sank and he barely escaped with his life, only to meet still further disasters in another land. Dr. Thomas, the other member of this expedition, has succeeded in conveying the disease to the chimpanzee by the bites of infected mosquitoes, thus affording a lower animal to take the place of the human sacrifices made to discover the cause, and also offering a hope for a cure.

A third disease spread by mosquitoes is filariasis, a worm infection of the lymphatics and of the blood. The work of the school in this direction has been to describe a number of new species of filaria found in birds. This work is said to be in large part due to the observations of the late Dr. J. Everett Dutton, who so soon afterward made such important discoveries concerning two diseases of Central Africa.

The first of these African diseases, sleeping sickness, is spread by one of the biting tsetse flies. The cause of the infection, which had