PATHOGENIC BACTERIA. 



239 



nature, and are always liable to be clinging to external 

 objects, especially in cities and around dwellings. The 

 infection of a wound in this manner, when the suppuration 

 is of a spreading character, such as is most character- 

 istic of streptococcus infection, is known in every-day Ian- 



guage as " blood-poisoning." It is possible for infec- 

 tion to take place around hair-follicles through the un- 

 broken skin. In such instances the suppurative inflamma- 

 tion first shows itself in a minute red pimple with a hair in 

 the center. The pimple presently becomes a pustule. The 

 process may cease at this point, or it may be only the com- 

 mencement of a large carbuncle with a central slough. Such 

 infection has been produced experimentally on the human 



