THE ADVANCE OF SCIENCE 147 



Corps, Lieutenant Tulloch, has died from the disease 

 acquired by him in the course of an investigation of this 

 disease and its possible cure, which he was carrying out, 

 in association with other men of science, on the Victoria 

 Nyanza Lake in Central Africa. Lieutenant Tulloch was 

 sent out to this investigation by the Royal Society of 

 London, and I will venture to ask my readers to join 

 that body in sympathy for his friends, and admiration for 

 him and the other courageous men who risk their lives in 

 the endeavour to arrest disease. 



Trypanosomes are now being recognised in the most 

 diverse regions of the world as the cause of disease new 

 horse diseases in South America, in North Africa, in the 

 Philippines and East India are all traced to peculiar 

 species of Trypanosome. Other allied forms are re- 

 sponsible for Delhi-sore, and certain peculiar Indian 

 fevers of man. A peculiar and ultra-minute parasite of 

 the blood cells causes Texas fever, and various African 

 fevers deadly to cattle. In all these cases, as also 

 in that of plague, the knowledge of the carrier of the 

 disease, often a tick or acarid in that of plague the flea 

 of the rat is extremely important, as well as the know- 

 ledge of reservoir-hosts when such exist. 



The zoologist thus comes into closer touch than 

 ever with the profession of medicine, and the time has 

 arrived when the professional students of disease fully 

 admit that they must bring to their great and hopeful task 

 of abolishing the diseases of man the fullest aid from 

 every branch of biological science. I need not say how r 

 great is the contentment of those who have long worked 

 at apparently useless branches of science such as are 

 the careful and elaborate distinction of every separate kind 

 of animal and the life-history and structure peculiar to 

 each in the belief that all knowledge is good, to find that 



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