.360 BACTERIOLOGY 



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

 of hydrogen a slight growth at 37°, none at 20° 



Pathogenesis. 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 is a 

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

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

 liver and kidneyf:. 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 hyphaa. 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 flava. 



b. Do not grow on potato. 



3. Streptothrix Hofmatmi (Grviber) 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 (Lofiier) Schmorl. 



B. Grow in nutrient gelatin. 

 I. Gelatin liquefied. 



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

 agar. 



