346 



INFECTIVE DISEASES. 



described in another chapter (p. 147) ; but sufficient has been said to 

 show that bacteriological reports in which it is stated that the typhoid 

 fever bacillus has been found in water causing typhoid epidemics 

 must be accepted with great reserve ; and further, no one is justified 

 in stating that the typhoid fever bacillus is undoubtedly the cause 

 of typhoid fever. It is not found in every case of typhoid, it is 

 not found in the blood, but it is found in those tissues which are 





'■z%*'^^y--^^S^^B^MM 



Tig. 136. — Typhoid Bacilli in a Section oi' Intestine, invading theSobmucous 

 (T.J.) AND MusouLAK Layers (M.), x 950 (B.aumgaeten). 



commonly the seat of secondary invasion of epiphytic bacteria, 

 whose normal habitat is the intestinal canal. 



Lastly, as the disease does not exist in the lower animals, the 

 crucial test cannot be applied. The etiology of typhoid fever is 

 still enveloped in doubt, and the nature of the contagiam has not 

 yet been detei'mined. 



