THE CLASSIFICATION OF BACTERIA 335 



concentric, with a dark central portion ; later ragged granular clumps in 

 pits of liquefied gelatin, with granular or ciliate borders. Plates com- 

 pletely liquefied in 36-40 hours. Colonies quite like the preceding (4). 

 The liquefied gelatin becomes decidedly alkaline. 



Gelatin stab. Quite like Msp. comma, but liquefaction rather more rapid. 



Agar slant (neutral to phenolphthalein) . In 24 hours, colonies 1.5-2 mm., 

 smooth, glistening, opaque ; in 48 hours, growth dryer, wrinkled. 



Loffler's blood serum. In 24 hours, at 37°, a depressed line, not spreading due 

 to liquefaction, becoming dirty brown. 



Bouillon. Turbid, with a pellicle, alkaline. 



Potato. In 48 hours, at 37", very slight growth, dirty yellow — brownish, not 

 spreading. 



Litmus milk. Acid, coagulated, sometimes not coagulated. 



Pepton solution. In 24 hours, a strong indol reaction, alkaline to litmus. 



Pepton rosolic acid sobition. Color slightly intensified, or orange-red. 



Glucose bouillon. No gas. Grow more slowly under anaerobic conditions. 



Pathogenesis. Very pathogenic to pigeons and guinea pigs. Pigeons, 

 0.2-0.3 cc. of an agar suspension into pectoral muscle causes death in 

 16-18 hours. Muscle swollen with oedema of subcutaneous tissue; 

 muscle marked by yellow striations and red necrotic areas ; bacilli 

 present in large numbers. Blood clots in the heart; lungs, kidneys, 

 and spleen quite normal ; intestines scarcely affected. Subcutaneous 

 inoculations of 0.3-0.5 cc. of an agar suspension into guinea pigs causes 

 death in 18 hours. Tissues at the point of inoculation much injected. 

 The subcutaneous oedema may be widespread or less so. Lymph 

 glands red and enlarged. Peritoneum red, or a general peritonitis with 

 perhaps much fibro-purulent exudate. The liver may be pale and 

 mottled or normal. Kidneys and adrenal bodies usually acutely con- 

 gested ; lungs and spleen normal. Bacilli in the fluid at the point of 

 inoculation, and sparingly in the blood and organs. 



Habitat. Isolated from Schuylkill River water. 



The preceding may be a variety of Msp. Metschnikovi, but Abbott claims a 

 distinct species. 



6. Microspira comma (Koch) Schroter 



Comma Bacillus Koch : Berliner klin. Wochensch., 1884, 31-32. 

 Spirillum cholerm-dsiatic'cB Zopf ; Spaltpilze, 1885. 

 Microspira comma Schroter : Pilze Sohles., 1886, 168. 

 Vibrio cholera Lehmann-Neumann : Bak. Diag., 1896, 317. 



Morphology. Bacilli 0.4 : 2.0 /u,, slightly curved — semicircular forms, also 

 spirals and involution forms. One or two spiral flagella. Not stained 

 by Gram's method. 



