BACTERIA IN DISEASE. 177 



are capable of carrying bacteria on their feet. The organisms 

 experimented with were typhoid, swine fever, staphylococcal 

 afiscess, pulmonary tuberculosis and anthrax. L. O. Howard* 

 and many others before and since have pointed out the same 

 source of danger of spreading of infection. To what extent 

 diseases are disseminated by fleas, bedbugs and similar crea- 

 tures is still uncertain. 



In this connection it is proper to refer to certain diseases due 

 to animal microorganisms. Malaria is conveyed from man to 

 man by mosquitoes of the genus Anopheles,f and is probably 

 transmitted exclusively in this manner. The parasite of 

 malaria undergoes part of its cycle of development in man, 

 and another part in the mosquito. Similarly, in Texas fever, a 

 disease of cattle, it has been shown by Theobald Smith that the 

 parasite (a protozoon, Pirolasma) passes from cow to cow 

 through the cattle-tick (Bophilus annulatus or bovis).J In 

 surra, a disease chiefly affecting horses, and in the tsetse-fly 

 disease of animals the parasite (a protozoon, Trypanosoma) is 

 transmitted by the bites of flies. It has been shown that the 

 infectious agent of yellow fever may be introduced into man by 

 mosquitoes of the genus Stegomyia.|| Under the administra- 

 tion of the United States army yellow fever was suppressed in 

 Havana chiefly by measures intended to prevent the disease 

 from being carried by mosquitoes. Equally good results have 

 since been attained in controlling an epidemic of yellow fever 

 at Laredo, Texas, in 1903,^ and a great reduction in the 

 mortality at Rio Janeiro, Brazil, has been effected. 



Auto-infection. It is possible for the bacteria of a disease 

 which is localized in one part of the body to be conveyed to 



*Lancet. July 27, 1907. Abstract in Journ. Am. Med. Assn., Aug. 24, 1907. 

 fFor detail concerning mosquitoes consult the book of Dr. L. O. Howard. 

 McClure, Phillips & Co. 



|See V. A. Moore. Infectious Diseases of Animals. 1902. 

 Report on Surra. U. S. Bureau of Animal Industry. 1902. 

 | (Carroll. Journal American Medical Association. May 23, 1903. 

 ^[Guiteras. Journal American Medical Association. July, 9, 1904. 

 12 



