14 PROTOZOOLOGY 



flagellate was observed in the blood of salmon by Valentin in 1841, 

 and the frog trypanosome was discovered by Gluge (1842) and 

 Gruby (1843), the latter author creating the genus Trypanosoma 

 for it. 



The gregarines were a little later given attention by Kolliker 

 (1848) and Stein (1848). The year 1849 marks the first record of 

 an amoeba being found in man, for Gros then observed Entamoeba 

 gingivalis in the human mouth. Five years later, Davaine found 

 in the stools of cholera patients two flagellates (Trichomonas and 

 Chilomastix). Kloss in 1855 observed the coccidian, Klossia heli- 

 cina, in the excretory organ of Helix; and Eimer (1870) made an ex- 

 tensive study of Coccidia occurring in various animals. Balantidium 

 coli was discovered by Malmsten in 1857. Lewis in 1870 observed 

 Entamoeba coli in India, and Losch in 1875 found Entamoeba histo- 

 lytica in Russia. During the early part of the last century, an epi- 

 demic disease, pebrine, of the silkworm appeared in Italy and France, 

 and a number of biologists became engaged in its investigation. Fore- 

 most of all, Pasteur (1870) made an extensive report on the nature of 

 the causative organism, now known as Nosema bombycis, and also on 

 the method of control and prevention. Perhaps this is the first scien- 

 tific study of a parasitic protozoan which resulted in an effective 

 practical method of control of its infection. 



Lewis observed in 1878 an organism which is since known as 

 Trypanosoma lewisi in the blood of rats. In 1879 Leuckart created 

 the group Sporozoa, including in it the gregarines and coccidians. 

 Other groups under Sporozoa were soon definitely designated. They 

 are Myxosporidia (Butschli, 1881), Microsporidia and Sarcosporidia 

 (Balbiani, 1882). 



Parasitic protozoology received a far-reaching stimulus when 

 Laveran (November, 1880) discovered the microgamete formation 

 ("flagellation") of a malaria parasite in the human blood. Smith and 

 Kilborne (1893) demonstrated that Babesia of the Texas fever of 

 cattle in the southern United States was transmitted by the cattle 

 tick from host to host, and thus revealed for the first time the close 

 relationship which exists between an arthropod and a parasitic proto- 

 zoan. Two years later Bruce discovered Trypanosoma brucei in the 

 blood of domestic animals suffering from "nagana" disease in Africa 

 and later (1897) demonstrated by experiments that the tsetse fly 

 transmits the trypanosome. Studies of malaria organisms continued 

 and several important contributions appeared. Golgi (1886, 1889) 

 studied the schizogony and its relation to the occurrence of fever, 

 and was able to distinguish the types of fever. MacCallum (1897) 



