360 BACTERIOLOGY 



Potato. A soft flat whitish growth, becoming brownish. In an atmosphere 

 of hydrogen a slight growth at 37 , none at 20'. 



I'athogenesis. Subcutaneous inoculation of guinea pigs causes abscesses at 

 the point of injection containing the bacilli, but without fatal issue. Intra- 

 peritoneal inoculations of mice cause death after some days. There 

 serous fluid in the peritoneal cavity ; the peritoneum is studded with sub- 

 milliary nodules. Spleen swollen, and studded with knots. Knots in 

 liver and kidney?. Bacilli in the lesions. 



STREPTOTHRIX 



Cells in their ordinary form as long branched filaments. Cultures on solid 

 media raised. Growth coherent, dry, rough, or crumpled, often with a 

 mouldy appearance, due to the formation of aerial hyphas. Without 

 endospores, but by a multiple segmentation of a filament, the production 

 of short, gonidia-like bodies. 



SYNOPSIS OF THE GENUS 



I. In the animal body the radially arranged filaments show a clavate enlarge- 



ment of their ends. 



A. Cultures show abundant branched filaments. 



1. Grow at room temperatures, 2o-22, and on potato. 



1. Streptothrix bovis (Harz) . 



2. No growth below 22 C. 



a. Grow on potato. 



2 . Streptothrix /lava . 



b. Do not grow on potato. 



3. Streptothrix Hofmanni (G ruber) Kruse. 



B. On ordinary media, viz. agar, no branched filaments, but diphtheria- 



like forms. 



4. Streptothrix Israeli Kruse. 



5. Streptothrix Krausei. 



II. Filaments do not show a clavate enlargement of their ends. 



A. Do not grow in nutrient gelatin ; grow on blood serum or blood- 



serum agar. 



6. Streptothrix necrophorus (Ldffler) Schmorl. 



B. Grow in nutrient gelatin. 

 I. Gelatin liquefied. 



a. Non-chromogenic, colonies whitish ; no pigment on gelatin or 

 agar. 



