XI] BACILLI : SPECIFICALLY PATHOGENIC 245 



on potato, and in 25 per cent, gelatine (at 37" C.) do not 

 correspond to the above tests. In respect of the rapidity of 

 growth of the colonies in gelatine plates and in gelatine 

 streak a latitude may be excusable, since in these respects 

 continued subcultures of the typhoid bacillus on artificial 

 media show that in respect of rate of growth it does some- 

 what alter with age, but not in respect of greater translucency ; 

 nor have I seen any alteration, after two or three years of 

 continued subcultivation, in the matter of flagella, of gelatine 

 shake culture, of milk-, broth-, potato-, or 25 per cent, gela- 

 tine cultures. It may be added that bacillus coli has longer 

 vitality, both in water and in sewage, than bacillus of 

 typhoid, and also that, while bacillus coli requires 65° C. for 

 five minutes to become killed, the typhoid bacillus is killed 

 already at 62° C. in five minutes. 



The identification by Dr. Horton Smith of the typhoid 

 bacillus from the urine of cases of typhoid fever was based on 

 the above characters, and his results are very instructive : — 



(a) In two cases of undoubted typhoid fever — mild 

 cases — the examination of the urine — always considerable 

 quantities being examined by Parietti's method — com- 

 mencing from the first week of illness and carried on till 

 the temperature again became normal, revealed no typhoid 

 bacillus. 



(6) One case, dead from typhoid fever during the third 

 week ; the urine taken in the post-mortem room yielded 

 numbers of colonies of the typhoid bacillus. 



(c) One case, first examined on the twelfth day of illness, 

 did not yield the typhoid bacillus, but, beginning with the 

 fourteenth day, till the twenty-second day, — the day of fatal 

 issue — yielded typhoid colonies. 



(d) One case, examined first on the tenth day of illness 

 and continued through the whole of the first attack and 



