CHAPTER XIV 



PRACTICAL APPLICATIONS 

 Staphylococcic Infections. 



COMMON as is disease due to the staphylococcus (boils, carbuncles, 

 pustular acne, osteomyelitis, etc.), our knowledge of the inner 

 mechanism of the pathogenicity of this organism is still somewhat 

 scanty. The only toxins definitely known to exist are a staphylo- 

 lysin and a leucocidin. The former is produced in three or four 

 days in faintly acid broth, and reaches its maximum in about 

 fourteen days. It is destroyed by a temperature of 56 C., and in 

 other respects resembles the true toxins. Many animals, and 

 notably the horse, contain a natural antistaphylolysin, which 

 neutralizes the action of this haemolysin, and is apparently a true 

 antibody. It is present in human serum, and may perhaps 

 account for the fact that anaemia is not a striking feature of 

 Staphylococcic diseases. Animals from which it is absent, such 

 as the rabbit or goat, can be made to produce it by immuniza- 

 tion with solutions of the lysin. Leucocidin is produced under 

 the same conditions as the hsemolysin, and the two are usually 

 produced side by side ; but they are distinct substances, the former 

 being the more easily destroyed by heat. Its action is not 

 entirely specific : it kills the leucocytes and dissolves them, but 

 has also some action on the ganglionic and other cells. As in the 

 case of the haemolysin, a natural antibody exists in the serum of 

 man, the horse, etc., and can be prepared from other animals. 



These substances, especially perhaps the latter, may play some 

 role in the production of disease, in that they may inhibit phago- 

 cytosis by a poisonous action on the leucocytes. But there 

 is little doubt that there is some other toxic body, probably an 

 endotoxin, since young cultures killed by heat, as used for vaccines, 

 are decidedly toxic, causing local irritation, and, if used in large 

 doses, a rise of temperature. These vaccines contain no haemo- 

 lysin or leucocidin. 



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