PARASITIC BACTERIA. 



161 



under various names chills and fever, autumnal 

 fever, etc. This disease, so common almost 

 everywhere, has been studied by physicians and 

 scientists for a long time, and many have been 

 the causes assigned to it. At one time it was 

 thought to be the result of the growth of a bacte- 

 rium, and a distinct bacillus was described as pro- 

 ducing it. It has finally been shown, however, 

 to be caused by a microscopic organism belong- 

 ing to the group of unicellular animals, and some- 



FlG. 34. Malarial organism : Figs, a to g show the growth of 

 the parasite within the blood corpuscle ; o is the organism in 

 all cases ; s, the spores. Fig. i is the so-called cresentic body 

 which develops through Fig. 2, into the flagellate form, shown 

 at 3. The significance of i, 2, and 3 are not known. 



what closely related to the well-known amoeba. 

 This organism is shown in Fig. 34. The whole 

 history of the malarial organism is not yet known. 

 The following statements comprise the most im- 

 portant facts known in regard to it, and its rela- 

 tion to the disease in man. 



Undoubtedly the malarial germ has some 

 home outside the human body, but it is not yet 

 very definitely known what this external home is; 

 nor do we know from what source the human para- 



