THE PATHOGENIC BACTERIA. 99 



What are active and passive immunity ? 

 What artificial methods are used to produce immunity? 

 What is meant by inoculation? Vaccination ? Intoxication ? 

 How does tissue suspension produce immunity ? 



What influence does the injection of inert particles have upon immunity? 

 What is meant hy forced immunity ? 



What is meant by an antitoxic serum ? By an antimicrobic serum ? 

 What classes of disease are protected against by antitoxic serum? What 

 by antimicrobic serum ? 



How is this anti-action explained? 

 What is the theory of abstraction ? 

 What is meant by the retention theory ? 

 What is the theory of Metchnikoff ? 

 What is Ehrlich's chain-theory? 



CHAPTER VIII. 



THE PATHOGENIC BACTERIA. 



THE PYOGENIC MICROCOCCI AND ALLIED BACILLI. 



THE most commonly found bacteria in pus are cocci (pyo- 

 cocci). A few are bacilli. The list includes: 



1. The Staphylococcus pyogenes aureus, albus, and citreus ; 

 the Staphylococcus cereus albus 9 the Staphylococcus cereus 

 aureus (Passet) ; the Staphylococcus cereus flavus (Passet). 



2. The Micrococcus pyogenes tenuis (Rosenbach). The 

 Micrococcus tetragenus is sometimes found associated with 

 the foregoing two varieties in abscesses or in pus cavities, 

 and are also able to produce abscesses at the place of injec- 

 tion in animals. 



3. The Streptococcus pyogenes is found associated with the 

 staphylococci in purulent accumulations, and is sometimes 

 itself responsible for pus-production in the body. 



4. The gonococcus is the cause of specific suppuration of 

 the urethra and often elsewhere in the body. 



5. The pneumococcus is often found in abscesses which 

 occur in the course of the disease in pneumonic patients. 



6. 7, and 8. The Bacillus pyocyaneus, typhosus, and tuber- 

 culosis are sometimes the cause of pus-production, as pure 



