628 



Bacillus Murium 



Cultivation. The bacillus can be grown upon the usual media. It grows read- 

 ily at ordinary room temperatures, but best at 37C. 



Colonies. Upon gelatin plates it forms rounded, transparent, granular col- 

 onies, which during the first three or four days somewhat resemble leukocytes. 

 The granular appearance becomes continuously more marked, and usually an 

 opaque central or peripheral nucleus is seen. In time the entire colony becomes 

 opaque, but does not liquefy gelatin. 



Gelatin. Stroke cultures on obliquely solidified gelatin show brilliant, opaque, 

 white colonies resembling drops of milk. The medium is not liquefied. 

 Bouillon. In bouillon it develops slowly, without either pellicle or flocculi. 

 Agar-agar. The culture upon agar-agar is said to be characteristic. 



The peculiar and characteristic appearances of the 

 colonies do not develop if grown at 37C.; but at 20 to 

 22C. the colonies appear rounded, whitish, opaque, and 

 prominent, like drops of milk. This appearance of the 

 colonies also shows well if the cultures are kept for ,the 

 first twelve to sixteen hours at 37C., and afterward at 

 the room temperature, when the colonies will show a flat 

 central nucleus transparent and bluish, surrounded by a 

 prominent and opaque zone, the whole resembling a drop 

 of sealing-wax. Sanarelli refers to this appearance as con- 

 stituting the chief diagnostic feature of Bacillus icteroides. 

 It can be observed in twenty-four hours. 



Blood-serum. Upon blood-serum the growth is very 

 meager. 



Potato. The growth upon potato corresponds with that 

 of the bacillus of typhoid fever. 



Vital Resistance. It strongly resists drying, but dies 

 when exposed in cultures to a temperature of 60 C. for a 

 few minutes, and is killed in seven hours by the solar rays. 

 It can live for a considerable time in sea-water. 



Metabolism. The bacillus is an optional anaerobe. It 

 slowly ferments dextrose, lactose, and saccharose, form- 

 ing gas only in dextrose solutions in which there are no 

 other sugars. It does not coagulate milk. In the cultures 

 a small amount of indol is formed. 



Pathogenesis. The bacillus is pathogenic for the do- 

 mestic animals, all mammals seeming to be more or less 

 sensitive to it. Birds are often immune. White mice are 

 killed in five days, guinea-pigs in from eight to twelve 

 days, rabbits in from four to five days, by virulent cultures. 

 The morbid changes present include splenic tumor, hyper- 

 trophy of the thymus, and adenitis. In the rabbit there 

 are, in addition, nephritis, enteritis, albuminuria, hemo- 

 globinuria, and hemorrhages into the body cavities. 



Sanarelli states that the dog is the most susceptible animal. 

 When this animal is injected intravenously, symptoms ap- 

 pear almost immediately and recall the clinical and ana- 

 tomic features of yellow fever in man. The most prominent 

 symptom in the dog is vomiting, which begins directly after 

 the penetration of the" virus into the blood, and continues 

 for a long time. Hemorrhages appear after the vomiting, 

 the urine is scanty and albuminous, or is suppressed shortly 

 before death. Grave jaundice was once observed. 



BACILLUS TYPHI MURIUM (LOFFLER) 



General Characteristics. A motile, flagellated, non-sporogenous, non-liquefy- 

 ing, non-chromogenic, non-aerogenic, aerobic and optionally anaerobic bacillus, 

 pathogenic for mice and other small animals, staining by the ordinary methods, 

 but not by Gram's method. It acidulates but does not coagulate milk. 



Bacillus typhi murium was discovered by Lorner* in 1889, when it created havoc 

 among the mice in his laboratory at Greifswald. 



* "Centralbl. f. Bakt. u. Parasitenk.," xi, p. 129. 



Fig. 256. Cul- 

 ture of Bacillus 

 icteroides on agar 

 (Sanarelli). 



