382 ■ BACTERIOLOGY. 



Colon Bacillus (p. 352). 



Diagnosis. — The motility of the colon bacillus distinguishes it 

 from the aerogenes group of bacteria, which includes well known 

 intestinal bacteria, such as the B. lactis aerogenes, and the B. coli 

 immobilis. The latter forms tend to produce convex raised growths on 

 the surface of gelatin in plate and stab cultures, whereas the motile 

 colon bacillus is more likely to give a thin spreading growth. The 

 variable motility of the colon bacillus, the influence of temperature, 

 and the consistency of the gelatin influence the cultural characteris- 

 tics to such an extent as to make this distinction of but little value. 



The colon bacillus is to be especially distinguished from the 

 typhoid and similar bacilli. The distinctions are given at length in 

 Chapter XIII. Acid, gas and indol production as well as coagulation 

 of milk are important characteristics. 



Eberth Bacillus (p. 354). 



Infection. — Commonly takes place through the mouth by means 

 of water, food, contact with soiled articles, etc. Air transmission, 

 as fine dust, is possible. Danger from flies and other insects. In 

 later stages other organisms as streptococci frequently appear — 

 mixed infection. 



Diagnosis. — The differentiation of the Eberth from the colon 

 bacillus is difficult and necessitates a comparison of all known reac- 

 tions (See Chapters XIII and XIV). The recognition of the disease 

 is based primarily upon the serum reaction (Chapter XV) and to less 

 extent, as yet, upon the isolation of the bacillus from urine or feces. 



Bacillus Icteroides (p. 356).' 



Pathogenesis. — It is very pathogenic for white mice, rabbits, 

 guinea-pigs. Dogs, monkeys, goats, sheep and horses are also sus- 

 ceptible. In guinea-pigs 1 c.c. of a 24 hour bouillon culture, intro- 

 duced subcutaneously or into the peritoneal cavity, produces death 

 in from 4-7 days. Virulent cultures, obtained by frequent transplan- 

 tations, will kill in less than 24 hours. In the latter case the bacilli 

 are extremely numerous on the serous surf 5.ces, in the blood and in- 

 ternal organs— septicemia. When death is delayed they are very 

 scarce, and little or no peritoneal effusion exists. ■ 



