COLON BACILLUS. 463 



The blood acquires specific agghitinins during 

 the course of infection. Even eight days after the 

 beginning of symptoms agglutination may be ob- 

 tained in dilutions varying from 1/200 to 1/4000. 

 The agglutinins disappear very rapidly. Working 

 with artificially prepared immune serum, Drigal- 

 ski determined the existence of coagglutinins for 

 typhoid and paratyphoid bacilli. 



We should bear in mind the likelihood that 

 meats poisoned with Bacillus enteritidis, as well as 

 by paratyphoid bacilli, may be encountered in 

 America, as well as in foreign countries. 



V. BACILLUS COLI 



Bacillus coli } or the colon bacillus, is the type of 

 a large group of organisms the members of which 

 show individual differences, but possess certain 

 dominant features in common. The typical colon 

 bacillus ferments various sugars, with the produc- 

 tion of gas, is a strong acid producer and curdles 

 milk. It is flagellated, has moderate motility and 

 does not stain with Gram's method. One type or 

 another is the normal inhabitant of the intestinal 

 tract of many animals, and, although the organ- 

 isms are widely disseminated in nature, their 

 occurrence is related directly or indirectly to the 

 distribution of feces. 



Its optimum temperature for growth is 37 C., 

 and above 46 C. it does not proliferate. It is 

 killed at a temperature of from 60 to 61 C. in 

 from five to fifteen minutes; it is not killed by 

 such low temperatures as from 20 to 24 C. 

 It resists absolute desiccation for periods varying 

 from a few days to several months (different ob- 

 servers). Direct sunlight kills 99 per cent, of the 

 germs in two hours (Billings and Peckham), and 



