TISSUE CHANGES PRODUCED BY BACTERIA. 147 



EFFECTS OF BACTERIAL ACTION. 



These may be for convenience arranged in a tabular 

 form as follows : 



Tissue Changes. 



(1) Local changes, i.e., changes produced in the 



neighbourhood of the bacteria. 



Position (a) At primary lesion. 

 (b) At secondary foci. 



Character (a) Vascular changes and tissue^ Acute 



reactions or 



(b) Degeneration and necrosis j Chronic. 



(2) Produced at a distance from the bacteria by 



absorption of toxines. 



(a) In special tissues, e.g., nerve cells and fibres, 



secreting cells, vessel walls, etc. 

 (b} General effects of malnutrition, etc. 



Symptoms. 



(a) Associated with known tissue changes. 



(b) Without known tissue changes. 



Tissue Changes produced by Bacteria. The effects of 

 bacterial action are so various as to include almost all 

 known pathological changes. They may be classified as 

 local effects or lesions produced in the neighbourhood of 

 the bacteria, and general changes which are produced in 

 various parts of the system by the circulation of the bacterial 

 products. As already stated, both the local and the general 

 effects are due to the products of the bacteria, but the 

 substances which produce local disturbances may not be 

 merely the same in more concentrated form as those 

 which act on distant parts of the system. In diphtheria, 

 for example, the products which produce the local inflam- 

 matory reaction and necrosis are probably not the same as 



