Bacillus Fusiformis is a long, rod-shaped organism measuring 5 to 10 by 0.6 to 0.8 µ, slightly swollen in the middle, and pointed at the ends. It stains readily with the ordinary dyes. The majority of observers state that it is Gram-negative, but others believe it to be Gram-positive. It is nearly always associated with the Spirochoeta vincenti.

Pathogenesis

This organism was described originally as occurring in cases of hospital gangrene. It is more common at present in the form of Vincent's angina (see p. 380), an inflammatory condition of the throat.

Cultures

It has been obtained in pure culture by growing upon the surface of ascitic fluid agar under strictly anaerobic conditions at 370 C. After two or three days the fusiform bacilli appear in the form of delicately whitish colonies, resembling colonies of streptococci. It has also been grown on rabbit's blood agar, and on Löffler's blood-serum. From all of the cultures a somewhat offensive odor is given off.