24O MANUAL OF BACTERIOLOGY. 



skin by rubbing in cultures of staphylococcus pyogenes 

 aureus. It is, furthermore, the constant experience of post- 

 mortem examiners that infection may occur around the hair- 

 follicles when no wound of the skin has been inflicted. 



In many instances, infection with the pyogenic bacteria 

 follows upon some preexisting infection; this happens, for 

 instance, in tuberculosis, when tuberculous lungs become 

 infected with streptococcus pyogenes, leading to the forma- 

 tion of a cavity. It is a common occurrence in gonorrhea, 

 after the acute stage of the disease has passed, when we 

 find the gonococcus in the pus, mingled with other pyo- 

 genic micrococci. Secondary infection with pyogenic bac- 

 teria is frequently due to the streptococcus pyogenes, often 

 also to the micrococcus lanceolatus. 



Sometimes we are obliged to admit that the manner in 

 which the pyogenic bacteria enter the body is unknown. 



The severe general symptoms, familiar to every physi- 

 cian, often accompanying acute suppuration, indicate the 

 formation of toxic bacterial products and their absorption. 

 Experimental evidence of the formation of such toxic prod- 

 ucts is not so clear, however, for the pyogenic organisms 

 as for some of the other bacteria. It has been shown that 

 cultures of staphylococcus pyogenes aureus, in which the 

 bacteria have been killed, are capable of producing suppura- 

 tion in the lower animals. 



The pyogenic bacteria play a somewhat different part in 

 producing disease, which is fully as important as the typ- 

 ical suppuration seen in an abscess. This happens when 

 the suppurative condition is mixed with other phenomena, 

 or when there is inflammation of another variety without 

 suppuration at all ; or there may be lesions not inflamma- 

 tory in a strict sense. These differences in their action 

 depend largely upon the organ affected. One such condi- 

 tion is osteomyelitis, which is, usually, suppuration occur- 



