Till: TYI'HOID BACILLUS 267 



Experiments indicate that the presence of other bacteria in the body, 

 and of exposure to the effect of noxious gases in lowering the natural 

 resistance of the individual, render him more susceptible to infection 

 from typhoid fever. 



Distribution of Bacilli in the Human Subject. Toxic Effects. 

 Typhoid fever belongs to that class of infectious diseases in which the 

 specific bacilli may occur throughout the entire circulation, as in septi- 

 caemia, or remain localized in certain regions in the body. Wherever 

 found in the tissues the typhoid bacilli are usually observed to be 

 arranged in groups or foci; only occasionally are they found singly. 

 These foci are formed, most probably, during life, as is proved by the 

 degenerative changes often seen about them; but it is possible that the 

 bacilli may also multiply somewhat after death. 



The inflammatory changes in the lymphoid tissue and other cellular 

 degenerations so often found in typhoid fever in the internal organs 

 are due to the effects of the soluble toxic substances eliminated by 

 the typhoid bacilli. The inflammation and ulceration of Peyer's 

 patches are the central feature, these being more directly under the 

 influence of the concentrated bacterial products. In typhoid fever 

 necrosis of the tissues of the internal organs is of comparatively rare 

 occurrence. Caseation of the mesenteric glands, which is commonly 

 observed, is due possibly to mixed infection. There are, however, a 

 number of cases now on record in which the typhoid bacillus has played 

 the part of pus producer. 



Unusual Location of Typhoid Lesions Occurring as Complications 

 of Typhoid Fever. Cases of sacculated and general peritonitis, sub- 

 phrenic abscess, osteomyelitis, periostitis, and inflammatory procesess 

 of other kinds have been reported as being due to the typhoid bacillus. 

 Kruse also reports an abscess of the spleen which contained only bacillus 

 typhosus, and typhoid abscess of the liver has been recorded by many. 

 In certain cases of typhoid pneumonia, serous pleurisy, empyema, and 

 inflammations of the brain and spinal cord or their membranes, typhoid 

 bacilli exclusively have occurred. The inflammation produced may or 

 may not be accompanied by the formation of pus. 



Such cases, however, are of comparatively rare occurrence, because 

 only exceptionally do the bacilli mass together in such numbers as 

 to become pus producers. As a rule, when such complications occur 

 in typhoid fever they are due to secondary or mixed infection with 

 the staphylococcus, pneumococcus, streptococcus, pyocyaneus, and 

 colon bacillus. Frequently these bacteria are found side by side with 

 the typhoid bacilli; in such cases it is difficult to say which was the 

 primary and which was the secondary infection. 



The distribution of the typhoid bacilli in different parts of the body 

 is explained by their passage through the circulation; and this is proved 

 by the bacilli being found in the earlier days of the disease in the spleen 

 constantly and frequently in the blood itself. 



The typhoid bacillus can be transmitted also from the blood of the 

 mother to the foetus. In one case reported by Ernst a living child, four 



