CHAPTER IX. 

 THE ACUTE SELF-LIMITED INFECTIONS. 



IN this chapter are included the infectious diseases which 

 are due to a specific microorganism and which tend to run a 

 definite course. 



BACTERIUM DIPHTHERLffi. 



Diphtheria is a disease caused by the Bacterium diphtheric?, 

 or diphtheria bacillus, or Klebs-Loffler bacillus, characterized 

 by the development of a so-called false membrane upon a 

 mucous membrane or abraded surface, from which the soluble 

 poisons are absorbed by the circulation. This false mem- 

 brane is an inflammatory exudate thrown out by the body 

 under the stimulus of the bacteria as a means of protection 

 against them. Myriads of bacteria are included in the 

 meshes of this exudate. If the false membrane be removed a 

 raw, bleeding surface is exposed. Sometimes this is done for 

 the purpose of applying remedial agents. The false mem- 

 brane of diphtheria appears most commonly upon the throat 

 and nose, but it may be found upon the eye, vagina, or skin 

 wound. 



This is the disease par excellence for explaining the effect 

 of toxins extracellular and separable from the bacteria. The 

 organisms do not enter the body but only their toxins are 

 absorbed, and are responsible for the clinical symptoms of 

 the illness, such as moderate fever with rapid pulse and 

 great prostration. They are also responsible for the paralyses 

 which frequently follow an attack, such as heart weakness 

 or laryngeal failure. 

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