NONSPECIFIC INFLAMMATION 315 



infection and suppuration in both man and animals are 

 sometimes caused by streptococci, although in most cases 

 staphylococci are more abundant. 



As a result of focal infections in various parts of the 

 body, more particularly in tonsils, about the teeth, and in 

 the sinuses, Streptococcus pyogenes may gain entrance to 

 lymph channels or the blood stream and localize in other 

 parts of the body. Most cases of articular rheumatism, for 

 example, are of this nature, the organism localizing and 

 growing in the membranes about the joints. Another 

 secondary effect following tonsilitis and similar infections 

 is endocarditis, that is, inflammation of the lining mem- 

 branes of the heart, including the membrane which covers 

 the various heart valves. In a certain proportion of cases 

 the latter leads to a deposition of fibrin upon the heart 

 valves, later the development of scar tissue and the warping 

 of the heart valves out of shape, resulting in leakage 

 through the valves. In most cases the organisms are finally 

 eliminated but the defective heart valve, of course, cannot 

 be repaired. This is one of the most common causes of heart 

 trouble. In some cases the fibrin collecting upon the heart 

 valves is considerable in amount. It may form small eauli- 

 flowerlike masses. Portions of this material occasionally 

 break away and pass into the blood stream. Such a particle 

 is termed an embolus and when it reaches a blood vessel 

 too small for its passage it may obstruct the flow of blood. 

 When this occurs in an end artery it may entirely cut off 

 the blood supply from that portion of the body. If this 

 should occur in the brain, for example, it would lead to 

 paralysis. 



Immunity. — Resistance to infection by streptococci 

 seems to be due principally to the activity of opsonins and 

 white blood cells. The problem is rendered complex by the 

 fact that there are many strains, varieties or perhaps even 

 species of streptococci and the opsonins or immune bodies 



