340 AGRICULTURAL AND INDUSTRIAL BACTERIOLOGY 



considerable losses to the poultry industry in the eastern 

 states. 



Typhoid-Dysentery Subgroup 



At least ten to fifteen species of bacteria are known which 

 belong to this subgroup. Only two among them, however, 

 are important from the standpoint of disease production. 

 Bacterium iypTii and Bacterium dysenterice, the latter with 

 numerous varieties. Two of the species, Bacterium gal- 

 Unarum, the cause of fowl typhoid, and Bacterium abortus, 

 the cause of infectious abortion in cattle, are of importance 

 in disease production in the lower animals. 



Bacterium typhi 



Synonyms. — Bacillus typhosus, Bacillus typTii, Bacillus 

 typJii-abdominalis, Eberth bacillus, Eberth Gaffky bacillus. 



This organism was discovered by Eberth in 1880 in the 

 spleens of those who had died of typhoid fever, and has 

 since been conclusively proved to be the cause of this dis- 

 ease. It is one of the most widely distributed of the organ- 

 isms producing disease in man, the disease being more or 

 less prevalent in most sections -of the United States. 



Morphology. — This organism is a short, plump rod, 

 usually from .5 to .8/t in diameter and from 1 to 3ju, in 

 length, motile by means of numerous flagella. It is non- 

 capsulated and does not produce spores. It is Gram- 

 negative and stains readily with the ordinary aniline dyes. 



Cultural Characters. — Bacterium typM grows readily 

 upon most of the cultural media, the growth being some- 

 what more delicate, usually, than that produced by Bac- 

 terium coli. 



Physiology. — Bacterium typhi grows best at blood heat, 

 but develops readily at room temperature. It is aerobic and 

 in the presence of suitable sugars a facultative anaerobe. 

 Acid, but no gas, is formed from dextrose, and neither acid 



