QUALITATIVE BACTERIOLOGICAL ANALYSIS. 231 



acquired by environment, and is not truly specific as in the case 

 of the B. typhosus, is shown by the fact that when the cultures 

 were removed from their associations and preserved for several 

 months on agar slopes, the sensibility to the agglutinins in the 

 anti-typhoid serum gradually declined, and at the end of six 

 months the results shown in the following table were 

 obtained : 



TABLE C. 



CULTURES OF B. COLI, FEOM TYPHOID STOOLS, RE-TESTED 

 WITH ANTI-TYPHOID SERUM AFTER BEING PRE- 

 SERVED FOR SIX MONTHS ON AGAR, 



The maximum dilution which caused complete agglutination 

 was now only 1100. The races of B. typiiosus, however, showed 

 no change, the results previously given were again obtained at 

 the end of six months. The culture B. typhosus G x was 

 peculiar; when first isolated from the spleen it only showed 

 traces of agglutination with the anti-typhoid serum diluted 

 1-50 ; but, after being preserved in milk for six months, a sub- 

 culture was completely agglutinated by the an ti- typhoid serum 

 diluted 1-1000. 



The typhoid culture G x was carefully studied, and it was 

 found to possess cultural characteristics absolutely identical 

 with undoubted races of B. typhosus. The cultural character- 

 istics of G x and the races of B. typhosus shown in Table B. are 

 given in Table D on pago 232. 



The cultural characteristics of the coliform cultures Nos. 62 

 to 69 were then examined ; it was thought that as they came 

 within the " typhoid range" as regards agglutination they 

 might show an approximation to the cultural reactions of 



