868 



PATHOGENIC MICROORGANISMS 



regarded by the first observers as representing two distinct forms 

 dwelling in symbiosis. 



The fusiform bacilli described by Vincent, Plaut, Babes, and others, 

 are from 3 to 10 micra in length, and have a thickness at the center 

 varying from 0.5 to 0.8 micron. From the center they taper grad- 

 ually toward the ends, ending in blunt or sharp points. The length 

 of these bacilli may vary greatly within one and the same smear 

 preparation. They are usually straight, sometimes slightly curved. 

 They do not stain very easily with the weaker anilin dyes, but are 

 readily stained by Loeffler's methylene-blue, carbol-fuchsin, or bet- 



FIG. 97. THROAT SMEAR, VINCENT'S ANGINA. Fusiform bacilli and spirilla. 



ter, by Giemsa's stain. Stained by Gram, they are usually de- 

 colorized, though in this respect the writers have found them to 

 vary. Stained preparations show a characteristic inequality in the 

 intensity of the stain, the bacilli being more deeply stained near 

 the end, and showing a banded or striped alternation of stained 

 and unstained areas in the central body. Their staining qualities 

 in this respect are not unlike those of the diphtheria bacillus, and 

 according to Babes 53 the dark areas are to be interpreted as meta- 

 chromatic granules. The bacilli are not motile. 



The spirilla found in Vincent's angina are usually somewhat 

 longer than the fusiform bacilli, and are made up of a variable 

 number of undulations, shallow and irregular in their curvatures, 



88 Babes, in Kolle und Wassermann, 1. Erganzungsband, 1907, 



