314 MICROBIOLOGY 



It has the property of acting on certain carbohydrates 

 producing acids and thereby it seems to be antagonistic to 

 certain putrefactive bacteria in the intestine. This hypothesis 

 has been quite clearly worked out, especially by Bienstock 12 

 and Tissier and Martelly. 13 



Resistance. Colon bacilli are killed at a temperature 

 of 60 C. in from five to fifteen minutes. Many of them are 

 destroyed by freezing but some individuals resist it for months. 

 They resist drying for months. They will grow in stronger 

 acid and alkali media than most bacteria. They are destroyed 

 by 5% carbolic acid or 1-1000 solution of corrosive sublimate 

 in about 2 minutes. 



Pathogenesis. Many cultures of B. coli are fatal to 

 guinea pigs of 900 grammes weight when inoculated subcu- 

 taneously in doses of 0.25 to 0.5 cc. of fresh (24 hour) bouillon 

 culture. Other cultures require the peritoneal injection of a 

 like quantity of the virus for fatal results. Some cultures do 

 not produce morbid changes when injected in doses of 1 cc. 

 into the peritoneal cavity. Moore found that more of the cul- 

 tures isolated from the intestines of dogs were virulent than 

 those obtained from the normal viscera of other animals. 

 Although the colon bacillus appears to have become localized 

 in the digestive tract of living animals (including man) and 

 to that extent become parasitic, it is not necessarily virulent as 

 determined by animal inoculation. B. coli has been isolated 

 from a large number of inflammatory lesions in animals. It 

 is believed to be the cause of many intestinal and other dis- 

 orders. It is apparently a frequent cause of localized in- 

 flammation and suppuration. Moore 14 described an outbreak 

 of disease among swine in which B. coli was apparently the 

 etiolcgical factor. It has been found that colon bacilli isolated 

 from an inflamed intestine were more virulent than those 



12 Bienstock. Archiv. f. Hyg., Vol. XXXIX (1900) p. 390. 



13 Tissier and Martelly. Ann. de 1'Inst. Pasteur, Vol. XVII (1902) 

 p. 865. 



14 Moore. Annual Report B. A. I., U. S. Dept. Agric., 1895-6, p. 

 218. 



