88 GUIDE TO THE STUDY 



various mammals but do not form the pigment which is charac- 

 teristic of the malarial organism. They undergo an essential 

 part of their life cycle in ticks and are transmitted by these 

 arthropods to the mammalian host. There will be demonstrated 

 (Babesia bovis) Piroplasma bigeminum, the cause of a widely 

 distributed and highly fatal disease of cattle known in this coun- 

 try as "Texas fever." The organisms are minute pear-shaped 

 bodies, usually two in a corpuscle. They vary in length from 

 2 to 4/x and in greatest width from 1.5 to 2 p.. This species was 

 the first of the group to be studied in detail and the first in 

 which was demonstrated the transmission of a protozoal disease 

 by an arthropod. 



References 



Good discussions of the malarial organisms of man are to be found in any 

 modern textbook of parasitology and in many of the medical texts. The 

 student who has access to a good library is advised to become acquainted 

 with the epochal early researches on the transmission of malaria by 

 mosquitoes. 



The following references will serve as a starting point for studies on bird 

 malarias: 

 Hegner, R., 1927. Experimental studies of bird malaria. Quart. Rev. 



Biol, 4 (1): 59-82. 

 Huff, C. G., 1927. Studies on the infectivity of plasmodia of birds for 



mosquitoes, with special reference to the problem of immunity in the 



mosquito. Am. Jour. Hyg., 7 (6): 706-734. 

 MacCallum, W. G., 1898. On the hsematozoan infection of birds. Jour. 



Exptl. Med., 3 (1): 117-136. 

 Smith, T., and F. L. Kilbourne, 1893. Investigations into the nature, 



causation and prevention of Texas or southern cattle fever. U. S. 



Dept. Agr., Bur. An. Ind., Bull. 1, 301 pp., 10 plates. 

 Whitmore, E. W., 1918. Observations on bird malaria and the patho- 

 genesis of relapse in human malaria. Johns Hopkins Hosp., Bull. 29: 



62-67. 



