TYPHOID FEVER 69 



TYPHOID FEVER 



Typhoid fever is caused by a bacillus which is variable in 

 length, though usually short (about half as long as a tubercle 

 bacillus) and thick, its length being only about three times its 

 breadth ; very long forms also occur, but in small numbers. It 

 does not form spores, and it does not stain by Gram's method. 

 It is actively motile ; when a culture of the organism in a fluid 

 medium is examined under the microscope, the bacilli can be 

 seen darting rapidly about in all directions. The bacillus owes 

 its motility to the possession of a large number of long, wavy 

 flagella, which can only be seen after special and difficult staining 

 processes. 



The B. coli communis, the most plentiful organism of the in- 

 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 perform- 

 ance 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 dis- 

 tinguish the one from the other by a prolonged and careful 

 examination of pure cultures. It is quite certain that the disease 

 might be diagnosed in this way ; indeed, it has been done, but the 

 task is an extremely difficult one, and the diagnosis would be 

 delayed for a considerable period.* 



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. coli. The specific bacillus occurs in the blood, spleen, spots, 

 mesenteric glands, liver, and frequently in the urine. 



It may often be demonstrated in the hlood, 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 



* Modern methods have greatly faciHtated the task, but even now it is only 

 used when other methods are unavailable, or for certain special purposes. 



