82 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



testine in man and animals, bears a very close resemblance to 

 the typhoid bacillus, and can only be distinguished therefrom 

 by the application of several cultural and chemical tests, the 

 performance of which takes a considerable amount of time. 

 This renders it very difficult to diagnose typhoid fever by 

 methods similar to those which are in use for the other 

 diseases mentioned i.e., by the demonstration of the specific 

 organism. Suppose, for instance, that we were to attempt to 

 determine the nature of a case of diarrhoea by a search for the 

 typhoid bacillus in the stools. For every typhoid bacillus 

 which we should encounter we should find a great many colon 

 bacilli, and we should only be able to distinguish the one from 

 the other by a prolonged and careful examination of pure eul- 

 tures. The disease may be diagnosed in this way; but the task 

 is a difficult one, and the diagnosis would be delayed for a 

 considerable period. The process has now been considerably 

 shortened, and is quite practicable, but calls for the services 

 of an expert. 



In other regions in which the typhoid bacillus occurs during 

 an attack of typhoid fever the search is usually facilitated by 

 the absence of other organisms, especially by the absence of 

 the B. coll. The specific bacillus occurs in the blood, spleen, 

 spots, mesenteric glands, liver, and frequently in the urine. 



It may often be demonstrated in the blood, and the method 

 is now acquiring some importance from the fact that positive 

 results are found to be very frequent if the examination is 

 made early in the disease i.e., within the first week. Thus it 

 is available before the Widal reaction appears, and should be 

 used wherever a positive diagnosis is required at a very early 

 date. The blood is drawn direct from a vein by one of the 

 methods described on p. 195, and at least 5 c.c. should be taken, 

 whilst 10 c,c. gives a greater probability of a successful result. 

 The best culture medium to employ is sterilized bile, which 

 inhibits the growth of many bacteria, whilst allowing that of 

 the typhoid bacillus. Procure ox-bile from the butcher, boil 

 half-hour in the steamer, filter, put into tubes (10 c.c. in each), 

 and sterilize in the autoclave or by intermittent sterilization in 

 the steamer. Broth containing -5 per cent, sodium citrate may 

 also be used. Growth will probably be seen in twenty-four 

 hours or less. If growth occurs the organism present has 

 next to be identified. Unfortunately, typhoid bacilli fresh from 



