CHAPTEK III. 



SOURCES OF INFECTION. 



PETTENKOFEB divided the pathogenic bacteria into two classes 

 the endo- and eeto-genous. Under the former head were classified 

 all bacteria which were supposed to have an endogenous origin, 

 while the ectogenous variety included all bacteria which enter the 

 organism from without. Syphilis and tuberculosis were regarded 

 as endogenous processes, but since it has been made possible to 

 cultivate the tubercle bacilli outside of the body and to produce 

 with them typical tubercular lesions, this disease cannot be 

 attributed any longer to an endogenous origin, and it will not be 

 long before future research will transfer syphilis from the endoge- 

 nous to the ectogenous variety for the same reason. Even in 

 the most marked cases of so-called auto-infection the microbes 

 must have entered the organism at some previous time from with- 

 out, and all such affections are in every sense of the word ectoge- 

 nous processes. In surgery it is of special importance that the 

 endogenous origin of infective diseases should be no longer recog- 

 nized, and that their causes should always be sought for outside of 

 the body. 



Bacteriology has rendered the term miasma obsolete. All infec- 

 tive diseases are now traced to an organic contagium. All infective 

 diseases in the strict sense of the word are contagious, as they can 

 only arise by the entrance of pathogenic microbes from without, 

 and this can only take place if they are brought in contact with 

 an absorbing surface. Of all substances which serve as a carrier 

 of microbes, the atmospheric air is the most important, because it 

 is present everywhere and no one can exclude himself from it. In 

 a dry state, pathogenic germs move with the currents of air and 

 attach themselves again to the solid or fluid substances with which 

 they come in contact. Although most of the microbes under 

 ordinary circumstances do not reproduce themselves outside the 

 body, their resistance to heat and cold, moisture and dryness, is so 

 great that they retain their disease-producing qualities often for an 

 indefinite period of time, and after their entrance into the body 

 and meeting with a proper nutrient medium they exert their spe- 

 cific pathogenic effects. 



Sternberg ( u The Thermal Death-point of Pathogenic Organ- 



