BACTERIUM 75 



Agar. — The growth on this medium is not vigorous. It is of a 

 neutral grayish color, with a glistening, moist appearing surface. It is 

 slightly viscid and adheres to the agar surface. Isolated colonies vary 

 from I to 2 mm. in diameter, nearly round, convex, with smooth and 

 sharply-defined margins. The condensation water becomes faintly 

 clouded with a. grayish sediment which becomes viscid. Within the 

 agar the colonies appear as minute grayish dots. In agar, especially in 

 plates (Petri dishes), it emits a peculiar, disagreeable, pungent odor. 



Gelatin.— OrAxnaxily it does not grow in gelatin. (Dr. Theobald 

 Smith found that certain cultures grew in this medium.) 



Potato. — It does not grow on potato. 



Botiillon. — Alkaline, peptonized bouillon becomes uniformly 

 clouded in 24 hours when kept at a temperature of 36° C. Occasionally 

 cultures are obtained in which the growth appears in the form of floc- 

 culent masses, but usually after a few generations these disappear and 

 the liquid becomes uniformly cloudy. If the bouillon contains any 

 dextrose or muscle sugar, its reaction becomes acid in 24 to 48 hours, 

 owing to the fermentation of the carbohydrate. With the virulent cul- 

 tures the liquid clears within a few days. The small amount of grayish 

 sediment becomes viscid after some days, and upon agitation it is 

 forced up, appearing as a somewhat twisted, tenacious cone, with its 

 apex at or near the surface of the liquid. Frequently a thin, grayish, 

 somewhat viscid band composed of bacteria is found on the sides of the 

 tube at the surface of the liquid. It will not grow in acid bouillon. If 

 the bouillon contains from i to 2 per cent, glucose, the growth is 

 slightly inore vigorous. 



Effects on sugars. — In the fermentation tube, alkaline bouillon con- 

 taining sugars becomes uniformly clouded in both branches. Gas is 

 not produced. In bouillon containing dextrose and saccharose the 

 reaction becomes strongly acid in 24 hours, but the reaction of alkaline 

 bouillon containing lactose is not changed. 



3lilk. — Milk inoculated with this organism remains unchanged in 

 appearance for several weeks. When boiled, after this period, the 

 casein is not coagulated. 



Indol. — This organism grows feebly in Dunham's solution ; some 

 cultures have given a decided indol reaction, but others have not. The 

 production of indol is reported to be one of the properties of the German 

 swine plague. Smith* obtained only a trace of indol in one out of four 

 cultures of swine-plague bacteria. 



Phenol.— ThXs was found by Lewandowski'sf method in all of the 



*Special report on swine plague, 1891, p. 89. 

 fDeutsche med. Wochenschrift, 1890, S. 1186. 



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