Physiology of Pathogenic Microbes. 61 



which they determiue in the corresponding glands. 

 But pathogenic germs can also penetrate directly 

 into the blood-vessels in which case generalization 

 occurs much more rapidly. 



CHAPTER II. 



PHYSIOLOGY OF PATHOGENIC MICROBES. 



1. Action of pathogenic microbes upon the organism. Receptiv- 

 ity. Immunity. — 2. Reaction of the organism against path- 

 ogenic microbes. Phagocytosis. Bactericidal condition. — 

 3. Evolution of the bacterial disease. 



I. Action of microbes upon the organism. 



MECHANISM OF THE PATHOGENIC ACTION. 



Pathogenic germs exert their action upon the 

 economy in two principal ways, of themselves, or by 

 their secretion products. We will consider, suc- 

 cessively, the mode of development of the troubles 

 which they occasion, both local and general. 



1. Pathogeny of local alterations. — In local lesions 

 the microbe acts at first like a foreign body, that is, 

 it excites a purely mechanical irritation; the Koch 

 bacillus very probably acts in this way when it gives 

 rise to tubercular neoplasms ; we know, indeed, that 

 the injection of lycopodium powder into the blood 

 develops a similar lesion, and the egg of the strongy- 

 liis vasorum appears to act in the same way in the 

 pseudo-tubercles which it occasions in the dog. 



