TYPHUS FEVER 



251 



angina," and because of this fact it is strongly suspected as the 

 etiological cause of the disease. The bacillus is a long, slender 

 organism, slightly curved, pointed at both ends, and somewhat 

 swollen in the center, presenting thus a spindle-shaped or fusiform 

 appearance (Fig. 34). It is non-motile and Gram negative. 

 Grown under anaerobic conditions it forms a whitish sediment in 

 broth ; on agar the colonies 

 have characteristic filament- 

 ous outgrowths. 



In film preparations made 

 directly from a lesion long 

 spirilla seem to be almost 

 as numerous as the fusiform 

 bacilli. When, however, cul- 

 ture medium is inoculated only 

 fusiform bacilli can be found. 

 The fact has given rise to 

 much speculation as to the 

 relation of the two forms. 

 Many investigators have con- 

 sidered the two organisms as distinct, but as having a symbiotic 

 affinity ; others have advanced the theory that the two forms are 

 only different phases in the life history of one organism. 



Fusiform bacilli associated with spirilla have also been found 

 in gangrene, noma, gingivitis, and dental caries. 



FIG. 34. Fusiform Bacilli and Spiro- 

 chetes. 



TYPHUS FEVER 



The disease, said by various writers to be one of the most highly 

 contagious of all febrile diseases, occurs principally under conditions 

 of overcrowding and filth. Formerly it appeared in epidemic 

 form. Improved sanitation, however, has greatly diminished its 

 occurrence ; and in some localities it has practically disappeared. 

 Infection is characterized by an incubation period of from five to 

 ten days, followed by a high temperature and petechial rash. 

 The body louse seems to be mainly responsible for its transmis- 



