G88 NON-PATHOGENIC BACILLI. 



In bouillon, when oxygen is excluded, an abundant development occurs at 

 37 C. at the end of twenty-four hours; the bouillon becomes clouded and 

 gives off stinking gases. 



403. BACILLUS POLYPIFORMIS (Liborius). 



Found in the soil by inoculations in mice, in the excrement, of cows, etc 

 Morphology. Slender bacilli of various lengths, a little more than 1 n 

 thick ; do not form filaments. 



Biological Characters. An anaerobic, non-liquefying bacillus ; ex- 

 hibits very slight independent motion. Forms long-oval spores, which oc- 

 cupy one-half to two-thirds of the length o the rods, and the diameter of 

 which is a little more than that of the bacilli. The colonies in gelatin con- 

 sist of small, yellowish masses with irregular, broad, flap-like projections ; 

 under the microscope these are seen to consist of variously twisted and bent 

 outgrowths, varying in thickness, which are given off in all directions like 

 the tentacles of a polyp; later these outgrowths increase in thickness. In 

 agar white colonies of irregular form, the size of a pin's head, are developed ; 

 under a low power these appear as finely granular, brownish, mulberry -like 



FIG. 230. Bacillus polypiformis; colony in nutrient gelatin, x 80. (Liborius.) 



masses. In blood serum a diffuse cloudiness is developed at the bottom of 

 the line of puncture. The addition of two per cent of sugar to culture 

 media favors the growth of this bacillus ; no gas is developed as a result of 

 its growth in such a medium. 



404. BACILLUS BUTYRICUS (Prazmowski). 



Synonyms. Bacillus amylobacter; Clostridium butyricum. 



Found in putrefying vegetable infusions, in old cheese and milk, in the 

 soil, etc. 



Morphology. Bacilli with round ends, from 3 to 10 n long and about 1 u 

 thick; frequently associated in chains ; also in filaments not apparently seg- 

 mented. The rods assume a spindle or tadpole form when spore formation 

 is about to occur, and may then be from 1.8 to 2.6 /Uhick; the spores are 

 oval, about 2 to 2.5 // long and 1 /u broad, and are located centrally or at one 

 extremity. When the spore vegetates a rupture of the exosporium occurs at 

 one of the poles, and the bacillus grows out in the direction of the long axis 

 of the reproductive element ; the empty spore case retains its form after the 

 vegetative cell is extruded. 



Biological Characters. An anaerobic, motile bacillus. Forms large oval 

 spores. Grows at the room temperature, in the absence of oxygen. The 



