248 BIOLOGY OF SPECIALIZED GROUPS 



mata (glanders, tuberculosis, actinomycosis, syphilis, and 

 leprosy) , there is only a small amount of vascular change but 

 a comparatively large amount of tissue hyperplasia. This 

 hyperplasia (increase in tissue cells) is principally noted in the 

 connective tissues. 



The general lesions in the body due to the toxins of bac- 

 teria are usually those of cloudy swelling and, sometimes, 

 fatty degeneration of parenchymatous organs, such as the 

 liver, kidney, etc. Capillary hemorrhages due to hyaline 

 changes in the arterial capillaries are also noted. 



Marked changes in the metabolism of the body are noted 

 in bacterial infections. Fever may be due either to the de- 

 struction of tissue or the formation of antibodies, etc. Pa- 

 ralysis, coma, spasms, are not uncommon in infections where 

 the nervous system is markedly affected. Disturbances of the 

 secretory functions of the various glands of the body are also 

 noted. 



The Poisonous Products of Bacteria. The poisonous 

 chemical substances produced by bacteria may be grouped 

 into four classes as follows : 



(a) Products of the decomposition of the media on which 

 the bacteria are growing. Ptomains and some other bodies are 

 produced in this way. 



(b) Soluble poisons, synthetically produced by the bacterial 

 cells and secreted by them into the surrounding media. The 

 true toxins are produced in this way. 



(c) Poisonous products synthetically produced by the bac- 



