154 SUPPURATION AND ALLIED CONDITIONS. 



numerous cocci being found in the capillaries of the various 

 organs, in which they often form plugs. If a smaller 

 quantity be used, the cocci gradually disappear from the 

 circulating blood ; some become destroyed, while others 

 settle in the capillary walls in various parts and produce 

 minute abscesses. These are most common in the kidneys, 

 where they occur both in the cortex and medulla as minute 

 yellowish areas surrounded by a zone of intense congestion, 

 and often haemorrhage. If one of these areas be examined 

 microscopically before actual suppuration has occurred, it 

 will be found that many of the capillaries are filled with 

 cocci, and the tissues immediately around are necrosed, 

 apparently by the action of the products of the organisms. 

 At the margin of the necrosed area there is a dense zone 

 of leucocytes. These gradually extend inwards and ulti- 

 mately purulent softening of the area occurs. The cocci 

 may reach the interior of the tubules, where they may be 

 often seen mixed with leucocytes, and in this way they reach 

 the bladder. Similar small abscesses may be produced in 

 the heart wall, in the liver, under the periosteum, and in 

 the interior of bones, and occasionally in the striped 

 muscles. Very rarely indeed, in experimental injection, do 

 the cocci settle on the healthy valves of the heart. If, 

 however, when the organisms are injected into the blood, 

 there be any traumatism of a valve or of any other part 

 of the body, there will be produced a special tendency for 

 them to settle at these weakened points. Though the 

 organisms are frequently seen completely -plugging the 

 capillaries, it is to be noted that this is often the result of 

 their multiplying after having settled in small numbers on 

 the endothelium in specially susceptible organs. Further 

 examples of the selection shown by different organisms 

 for different parts will be given in subsequent chapters. 



Experiments on the human subject have also proved the 

 pyogenic properties of those organisms. Garre inoculated 

 scratches near the root of his finger-nail with a pure culture, 

 a small cutaneous pustule resulting ; and by rubbing a 

 culture over the skin of the forearm he caused a carbun- 



