514 THE BACILLUS OF SOFT SORE 



SECTION II. MORPHOLOGY. 

 1. Microscopical appearance. 



The organism is a rather short bacillus with rounded ends measuring O5// 

 by 1*5 to 2/j. Two lateral notches are sometimes seen which give the organism 

 a figure-of-eight appearance. In pus it occurs singly or in a chain composed 



of three to twenty bacilli, and clumps may 

 be formed of chains crowded one against 



^s v another. The bacilli are generally free, but 



i x x it is not uncommon to find them inside the 



polynuclear leucocytes. In scrapings from 

 some soft sores the bacillus does not show its 

 V^ ordinary characteristics but assumes the form 

 of a coccus (Queyrat). 



In cultures on blood-agar the bacilli occur 

 singly or collected together in masses or in 

 short chains : in liquid serum they form 

 long wavy chains arranged like a skein of silk 

 (streptobacilli) : in the liquid at the bottom 

 of blood-agar tubes the bacilli are more slender 

 ? and the chains much longer. 



Staining reactions. The bacillus of soft 



sore is easily stained with the basic aniline dyes, but in the majority of 

 cases only the ends take up the dye leaving the centre unstained ( shuttle - 

 shaped bacilli). The bacillus is gram-negative. 



t 



Off * 

 9 



& 6 



gr*jS* 



FIG. 247. Bacillus of soft sore. Film FIG. 248. Bacillus of soft sore. Film 



from a culture on blood-agar. (After Be- from a liquid serum culture. (After Bezan- 



zancon, Griffon and Le Sourd.) con, Griffon and Le Sourd.) 



(a) Pus and cultures. Pus and cultures should be stained with carbol- 

 thionin, carbol-blue or carbol- violet and examined in water or balsam. 



Krefting recommends the following solution : 



5 per cent, solution of boric acid in water, - 16 c.c. 



Saturated aqueous solution of methylene blue, 20 ,, 



Distilled water, - 24 



Queyrat recommends the following mixture for smear preparations : 

 Carbol-fuchsin, - 10 drops. 



Saturated aqueous solution of methylene blue, 7 



Distilled water, - .-__.. 20 c.c. 



(b) Sections. The method recommended for staining sections is Nicolle's 

 tannin method (p. 217). Stain in Kiihne's carbol-blue then treat for a few 

 seconds with 10 per cent, tannin solution, wash in water, then in alcohol, 

 clear in clove oil and xylol and mount in balsam. 



