CHAPTER IV. 



LOCALIZATION OF MICROORGANISMS. 



EVERY surgeon has had frequent opportunities to observe cases 

 in which a slight subcutaneous injury was followed by a destructive 

 inflammation, an inflammation not produced by the trauma, but by 

 the localization of pathogenic microbes in the tissues altered by the 

 injury. Thus Chaveau (Comptes rendus, t. 76, p. 1092) has shown 

 experimentally that subcutaneous crushing of tissue furnishes a 

 favorable condition for the localization of pathogenic microorgan- 

 isms carried to the part by the circulating blood. When he injected 

 a putrid fluid directly into the circulation of young rams shortly 

 before subcutaneously crushing the testicle, the injured organ always 

 became the seat of septic gangrene, while without such injection 

 the crushed testicle disappeared by uecrobiosis and absorption. 

 Gangrene only occurred if the putrid fluid contained bacteria ; it 

 did not take place if the fluid was carefully filtered. Extensive 

 subcutaneous injuries, as severe contusions, rupture of tendons or 

 muscles, and crushing of bone, are not followed by suppuration, 

 unless the injured tissues become subsequently the seat of infection 

 with pus-microbes. A patient may have been the subject of tuber- 

 cular infection for an indefinite period of time, and yet may present 

 the appearances of ordinary health until some slight injury deter- 

 mines localization of the bacillus of tuberculosis in the part injured, 

 an occurrence which is followed by a localized tuberculosis from 

 which, later, regional and general dissemination takes place, to 

 which the patient finally succumbs, unless the tubercular focus is 

 removed by an early operation. These facts suggest very strongly 

 that, in the hypothetical cases, suppuration and tuberculosis would 

 not have taken place in the part injured without the injury, and 

 that the injury certainly would not have produced suppuration or 

 tuberculosis unless the respective patients had been infected pre- 

 viously with specific pathogenic microorganisms. The injury in 

 these cases creates a so-called locus minoris resistentice, which may 

 signify one of two things : 1. Diminution or suspension of resist- 

 ance on the part of the injured tissues to the action of pathogenic 

 microorganisms, which was present in the part at the time of injury ; 

 or, 2. The injury so alters the tissues that pathogenic germs, which 

 were present in the circulation without having given rise to symp- 



