236 AIDS TO BACTERIOLOGY 



must be borne in mind^that^typhoitTfever, as diagnosed 

 clinically, is not always due"* to a typical Eberth-Gaffky 

 bacillus, and should an organism be isolated differing in 

 one or two respects from the recognised characters of 

 this bacillus, the agglutination test should be performed 

 with the serum of a case supposedly infected through 

 the water. With an atypical typhoid bacillus a negative 

 Pfeiffer reaction with an animal receiving this bacillus 

 and the serum from an animal immunised against a typical 

 typhoid bacillus is of doubtful significance, as the reaction 

 is such a markedly specific one. 



The following organisms resemble the typhoid bacillus 

 morphologically and in cultural characters: 



Bacillus aquatilis sulcatus is distinguished from the 

 typhoid bacillus (1) by developing at 5 C.; (2) by growing 

 feebly at 37 C.; (3) by not agglutinating with typhoid 

 serum; and (4) by the colonies after a time acquiring a 

 yellowish colour. Several varieties have been described. 



Bacillus fcecalis alkaligenes does not agglutinate with 

 typhoid serum, and produces alkali in milk. Fuerth 

 describes a disease simulating typhoid produced by an 

 organism of this type. Savage mentions a single sporadic 

 case of gastro-enteritis that was shown by Ridder to be 

 probably caused by this organism. 



B. coli anaerogenes is dealt with elsewhere (pp. 93 and 

 108). 



Detection of the Cholera Vibrio. See p. 151. 

 Media used in the Examination of Water. The media 

 used for enumeration purposes should preferably be not 

 more than three weeks old, as changes occur in the reac- 

 tion with age. Such media are to have a reaction of 

 + 10. 



Nutrient Agar and Nutrient Gelatin. See p. 36. 

 Distilled- Water Gelatin. Ten per cent, gelatin in dis- 

 tilled water. 



Distilled- Water Agar. Powdered agar 1| per cent., dis- 

 solved in distilled water. 



Peptone-Water and Carbohydrate Peptone- Waters. See 

 p. 37. 



Litmus Milk. See p. 38. 



Neutral lied Broth. A J per cent, solution of neutral 

 red in water is added in the proportion of 1 c.c. to 

 every 100 c.c. of a broth containing 0'5 per cent, of glucose. 



