LEADING SCHOOL OF TROPICAL MEDICINE 339 



from the pigmented cells found in the stomach of the mosquito to the 

 rod-shaped bodies in the salivary glands. He then exposed birds free 

 from parasites to the bites of such infected mosquitoes, and fourteen days 

 later these birds had parasites in their blood. In this manner were 

 demonstrated the development of the malarial parasites in the mosquito, 

 the mode by which they were transmitted and the fact that not every 

 kind of mosquito will transmit the microscopic animal which causes the 

 disease. Although it was in birds that the complete life-cycle of the 

 organism was first followed, the pigmented cells which were a clue to 

 the discovery were first seen in man. 



A few months after his appointment at Liverpool, Professor Ross 

 left England for Sierra Leone, Africa, on the first of those expeditions 

 which have made the school famous. The purpose of the expedition 

 was to study still further the subject of malaria, but this time in the 

 human being. Mr. Austen, of the British Museum, accompanied him 

 for the purpose of collecting and studying the various kinds of mos- 

 quitoes and noxious insects. 



This first malarial expedition was followed by many other such 

 expeditions; and the value of the four measures for the prevention of 

 malaria advocated by Professor Ross may be seen in the results that 

 followed the expedition to Ismailia in 1902. Ismailia is a town of 

 under 6,000 inhabitants, situated close to the Suez Canal and controlled 

 by the Suez Canal Company. The number of cases there rose from 

 300 in 1877 to 2,250 in 1900. An active campaign of first detecting, 

 isolating and treating the sick; second, segregating the healthy; third, 

 mechanically protecting the well from mosquitoes; and fourth, reducing 

 the number of mosquitoes by drainage or other treatment of their 

 breeding places, begun in 1902, reduced the number of cases from 

 1548 to 37 in 1905; and all the old cases of 1905 were cases of relapse. 



In 1902, Professor Ross received a Nobel prize for his researches 

 on malaria. In 1906, he went on a malaria expedition to Lake Copais, 

 Greece, and in 1907, he was sent at the request of the Government of 

 Mauritius to give advice on the prevention of malaria in that island 

 of the Indian Ocean. It will thus be seen that the work of Professor 

 Ross is not only of scientific value, but thoroughly practical as well. 



Another malady closely associated with malaria is blackwater fever. 

 The classical description of this disease has been written by another 

 teacher of this school, Dr. Stephens, who, next to Professor Ross, has 

 done so much to spread a knowledge of malaria and tropical medicine. 

 In 1907, Dr. ISTierenstein, a chemist of the school, discovered certain 

 etiological factors in this malady; and in July of the same year, the 

 nineteenth expedition was sent to Africa to study blackwater fever. 



A second disease conveyed by mosquitoes is yellow fever, which is 

 distinctly American in origin. Pound by Cortez in Mexico and un- 



