194 WOUND INFECTION AND PYOGENIC BACTERIA 



may be even more serious results when the bacteria enter the general 

 circulation through the blood or lymph current. In this case their 

 multiplication and the toxin production in the blood itself causes 

 grave symptoms, generally including chills and severe fever of an 

 irregular type. This process of pyogenic microbes multiplying in the 

 general circulation is popularly known as "blood poisoning," and 

 technically as a septicemia. 



Another pathologic process which may follow wound infection 

 consists in the formation of small masses of bacteria, perhaps in com- 

 bination with small flocculi of pus or bits of necrotic tissue. These 

 are taken up by the circulation and carried along in the blood stream 

 until they finally become lodged in parts at a considerable distance 

 from the original focus of infection. In this manner the detached 

 masses of bacteria may be transported to the lungs, heart, liver, 

 kidneys, spleen, brain, or almost any one of the internal organs of 

 the body from foci of infection on an extremity or some other place on 

 the surface of the body. After they have finally become lodged, the 

 bacteria multiply and may give rise to secondary and generally mul- 

 tiple foci of inflammation and suppuration. This pathologic occur- 

 rence or process is known as the formation of multiple metastatic 

 bacterial emboli and the general condition of blood poisoning which 

 has now become established as a pyemia or septicopyemia. It is 

 more dangerous than a septicemia, and recovery is relatively rare. 



When pus from an acute suppurative process is examined the 

 causative bacteria are generally found in large numbers. This 

 makes it comparatively easy to draw an accurate conclusion as to the 

 nature of the particular infection. When more than one species of 

 bacteria is present, either from the beginning or very soon after, 

 the process is known as a mixed infection. An acute suppurative 

 process due to pyogenic bacteria may develop into a subacute or 

 chronic one. While the inflammation and suppuration may continue 

 the infecting bacteria may die out and disappear. The pus then 

 becomes void of living bacteria and is known as sterile pus. More or 

 less extensive masses of necrotic tissue which are always a source of 

 inflammatory irritation may, however, cause the inflammation and 

 suppuration to continue. When necrotic tissue is present, it may 

 become the soil for the development of purely saprophytic bacteria. 

 Gangrene may set in, and if a sufficient quantity of the putrefactive 

 products is absorbed a condition of sapremia may supervene. 



STAPHYLOCOCCUS PYOGENES. 



The most common pus-producing bacteria in man and animals 

 are the pyogenic staphylococci. 



Varieties. According to the pigments formed by these bacteria 

 they are distinguished as: 



