CHAPTER XXVI. 

 GROUP III. 



Acute infectious diseases in which acquired im- 

 munity of prolonged duration is not established. 

 In some instances soluble toxins are produced 

 which are of unknown importance in the infections 

 (staphylococcus, streptococcus). Some of the or- 

 ganisms contain rather strong endotoxins (pneu- 

 mococcus, gonococcus), whereas in others a reason- 

 able basis for their infectiousness is not at hand. 

 In some instances immunization causes increased 

 resistance to infection (staphylococcus, streptococ- 

 cus), whereas this property has not been fully 

 demonstrated in others. 1 The serums of immun- 

 ized animals may or may not be protective for 

 other animals. Those organisms which cause sys- 

 temic infection give rise to leucocytosis (except 

 influenza). Local inflammations are accompanied 

 by the accumulation of polymorphonuclear leuco- 

 cytes. 



I. PNEUMOCOCCUS INFECTIONS PNEUMONIA. 



No one organism is the exclusive cause of any 

 one type of pneumonia, except perhaps the viruses 

 of syphilis and tuberculosis. Any microbe which 

 causes pneumonia can also set up inflammations 

 in other organs. The following may cause acute 



1. This point is difficult of determination when an organ- 

 Ism has little or no pathogenicity for animals (influenza, 

 gonococcus, bacillus of Ducrey, etc.). 



