56 BACTERIA 



responsible for the causation of enteric (or typhoid) fever. 

 In 1885 the B. coli communis was recognised, and it has been 

 a nnatter of great debate amongst bacteriologists as to how- 

 far these two organisms are the same species, and the 

 typhoid germ merely a higher evolution of the B, coli. The 

 differentiating signs between them will be referred to shortly. 

 Bacteriologists generally regard the Eberth-Gaffky bacillus 

 as the specific cause of the disease, though complete proof 

 is still wanting. 



Microscopic Characters (in pure culture). Rods, 2-4 // long, 

 .5 }x broad, having round ends. Sometimes threads are ob- 

 servable, being 10 pi in length. In the field of the microscope 

 the bacilli differ in length from each other, but are all the 



Bacteria of Typhoid Fever 



same thickness approximately. Round and oval cells con- 

 stantly occur even in pure culture, and many of these shorter 

 forms of typhoid are identical in morphology with some of 

 the many forms of Bacillus coli. There are no spores. 

 Motility is marked ; indeed, in young culture it is the most 

 active pathogenic germ we know. The small forms dart 

 about with extreme rapidity ; the longer forms move in a 

 vermicular manner. Its powers of movement are due to 

 some five to twenty flagella of varying length, some of them 

 being much longer than the bacillus itself, though, owing to 

 the swelling of the bacillus under flagellum-staining methods, 



