18 GERMANY IN SCIENCE 



midwifery and later in surgery. 



Vaccination against small-pox is due to Jenner, an Eng- 

 lishman. 



In this connection we should not lose sight of the results 

 of the remarkable series of investigations which led to the 

 classification of the unicellular plants, known as bacteria or 

 bacilli, and the changes brought about by their presence in 

 organic substances, resulting in the formation of toxins and 

 antitoxins. The great names in bacteriology are those of Leeu- 

 wenhoek, a Hollander; Pasteur, a Frenchman; Marshall Ward, 

 Duguid, Burdon-Sanderson and Greenfield, Englishmen; 

 Metchnikoff, a Russian; Ravenel an American; Klebs, Lref- 

 fier, Koch, and Ehrlich, Germans. Koch had the honor of 

 discovering the bacillus of tuberculosis and of cholera. His 

 claim to have discovered a remedy for tuberculosis was after- 

 wards disproved, and his reputation became clouded. 



The disco very that malarial fever, so-called, is due to the 

 presence in the blood of the patient of a one-celled animal known 

 as Plasmodium malaria&^which is introduced into the circula- 

 tion through the agency of a species of mosquito belonging to 

 the genus Anopheles, and the kindred discovery that yellow fev- 

 er is produced by an animal, which is likewise transmitted by 

 a mosquito belonging to the genus Stegomyia,and the further 

 discovery that sleeping sickness and various deadly diseases 

 attacking man and other warm-blooded animals are due to 

 protozoans belonging to the genus Trypanosoma, which are 

 communicated by flies, are among the more recent results of 

 highly interesting researches, in which English, French, and 

 especially American investigators have played the chief role. 

 As a practical result of these discoveries it seems likely 

 that vast regions hitherto regarded as uninhabitable by men 

 may be reclaimed to their use. The Campagna about Rome, 

 the climate of which was deemed deadly, is rapidly being made 

 habitable, and its fertile soil is being made to bear crops, the 

 systematic disinfection of its mosquito-haunted pools by the 

 simple use of coal-oil applied to them having brought about a 



