TISSUE CHANGES PRODUCED BY BACTERIA 181 



directly or indirectly by them. This action is shown by tissue 

 '//'////AN produced in the vicinity of the bacteria or throughout 

 thr system, and ly /o.r/V *// mjitunis of great variety of degree and 

 character. 



We shall first consider the effects of bacteria on the body 

 generally, and afterwards the nature of the chemical products. 



KI-TKCTS OF BACTERIAL ACTION. 



These may le for convenience arranged in a tabular form as 

 follows : 



A. Tissue Changes. 



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



bourhood of the bacteria. 



Position (a) At primary lesion. 

 (6) At secondary foci. 



Character (a) Tissue reactions \ Acute or 



(b) Degeneration and necrosis/ chronic. 



(2) Produced at a distance from the bacteria, directly or 



indirectly, by the absorption of toxins. 



(a) In special tissues 



(a) as the result of damage, e.g. nerve cells 

 and fibres, secreting cells, vessel walls, or 



((3) changes of a reactive nature in the blood- 

 forming organs. 



(b) General anatomical changes, the effects of 



malnutrition or of increased waste. 



B. Symptoms and Cfianyes in Metabolism. 



The occurrence of fever, of errors of assimilation and 

 elimination, etc. 



A. Tissue Changes produced by Bacteria. The effects of 

 I 'arterial action are so various as to include almost all known 

 pathological changes. However varied in character, they may 

 be classified under two main headings : (a) those of a degenera- 

 tive or necrotic nature, the direct result of damage ; and (b) those 

 of reactive nature, defensive or reparative. The former are the 

 r.\l res<i<m of the necessary vulnerability of the tissues, the latter 

 of protective powers evolved for the benefit of the organism. In 

 the means of defence both leucocytes and the fixed cells of the 



