Bacillus Typhosus, Eberth, Koch (1880). 

 Bacillus of typhoid fevbh; koch-eberth's bacillus. 



Origin. — First obtained from the spleen and lymphatic glands of 

 typhoid fever cadavers; present in the blood, thougrh in small num- 

 bers; also in the feces and urine of typhoid patients. 



Form. — Good sized rods, 3-5 times as long- as wide, with rounded 

 •ends. The length varies greatly with the nature of the medium on 

 "which it grows. Thus, on agar it appears as very short rods, while on 

 the potato it may grow into long threads. Involution forms. 



Motility. — Is very actively motile; on ptolonged artificial cul- 

 ture it may show little or no motion. It has numerous lateral whips. 

 Excellent giant-whips. 



Sporulation. — Terminal, rounder oval bodies are found in potato 

 and agar cultures, which are groi^n in the incubator for several days. 

 They do not double stain and the bacilli containing these are very 

 susceptible to heat. They are not therefore true spores, but rather 

 little masses of condensed protoplasm (see p. 27). The bacilli are 

 very resistant to desiccation and may retain their vitality for months. 



Anilin dyes.— It does not stain as well with ordinary anilin dyes 

 as do most bacteria: carbolic fuchsin stains excellently. It does not 

 stain by Gram's method. Excellent bi-polar stain when grown on 

 potato; no plasmolyais (Migula). 



Growth. —Is less rapid, but in its cultural properties it greatly 

 resembles the preceding organism. Slow at 16-18°. 



Plates. — The deep colonies pn gelatin plates are small, round, or oval, sharply bor- 

 dered, finely granular and yellowish. They may show a central dark portion or ring. Fre- 

 quently, a protuberance or swelling will be seen on the border of the colony. At times deli- 

 cate fibrils may surround the border (see Eisner's medium). The surface colonies (crater- 

 like) spread freely as an almost transparent film, which has an irregular, wavy border, and 

 is delicately marked with branching lines. No liquefaction. For appearance of colonies on 

 Eisner's or on Stoddart's medium, see Chapter XIV.. 



Stab culture, — Abundant growth alon^ the entire line of inoculation, and especially 

 so on the surface where it spreads as a .thin, grayish white covering. Gelatin eventually 

 becomes cloudy, due to the production of acids. See also stab culture in Hiss^ mediujn. 



Streak culture. — On agar and on blood-serum it forms a moist, white growth, without 

 any special characteristics. On potato, as a rule, the growth is very characteristic. It 

 covers the surface as a moist, invisible layer— distinction from preceding organism. On 

 alkaline potatq, the growth is yellowish and no longer characteristic. For litmus lactose 

 agar see p. 241. 



Bouillon. — Slight diffuse': cloudiness, much less than with the colon bacillus. Very 

 little deposit and scarcely any ring or film. Remains, clouded for a long time. Unlike the 

 colon bacillus, it will not grow in bouillon which contains 20 c.c. of N HCl or 50 c.c'. of N 

 NaOH per liter. No indol is produced. No growth in Uschinsky^s medium. ' 



milk. — Is not coagulated. No gas in glucose media, nor acid in lactose media. 



Oxygen trequirements.— It is a facultative anaerobe. 



Temperature. — Grows well at ordinary temperature. Optimum 

 at 37°. Exposure of a few minutes to moist heat of 60° kills. 



Aerogenesis.— No acid or gas production on lactose media. 



Behavior to gelatin. — Does not liquefy. ^ 



Immunity. — As in cholera, injections of dead or living cultures 

 yield an anti-infectious serum, whereas injections of the toxin yield 

 an antitoxic serum. The serum in the former case will give Pfeitfer's 

 reaction with the Eberth, but not with the colon bacillus. 



Pathogenesis. — Intravenous injections usually kill rabbits. It is 

 usually fatal to guinea-pigs, when introduced into the previously 

 alkalized stomach, or when injected into the duodenum or into the 

 peritoneal cavity. Subcutaneous injections are also f ata'1%0 guinea- 

 pigs -distinction from the colon bacillus. The same method of infec- 

 tion will produce abscesses in rabbits and dogs. At times it produces 

 abscesses in man. Cultures killed with chloroform, or by heating at 

 54° for one hour are fatal to guinea-pigs in a dose' of 3-4 mg. per 100 g. 

 body-weight. 



Infection, Diagnosis. — See p; 382. 



354 



