STUDY OF PATHOGENIC BACTERIA 409 



sary familiarity with the cultural characters of impor- 

 tant bacteria be acquired. The study of the various 

 groups will of course vary in detail with individual 

 demonstrators, and with the student's requirements 

 the general line it should take is indicated briefly in 

 connection with the first group only (pages 410-411). 

 This section should be carefully worked through before 

 the student proceeds to the study of bacterioscopical 

 analysis. 



It is customary to commence the study of the patho- 

 genic bacteria with the Organisms of Suppuration. 

 This is a large group, for all the pathogenic bacteria 

 possess the power, under certain conditions, of initiat- 

 ing purely pyogenic processes in place of or in addition 

 to their specific lesions, (e. g., Bacillus tuberculosis, 

 Streptococcus lanceolatus, Bacillus typhosus, etc.). 

 There are, however, a certain few organisms which 

 commonly express their pathogenicity in the formation 

 of pus. These are usually grouped together under the 

 title of "pyogenic bacteria," as distinct from those 

 which only occasionally exercise a pyogenic role. 



The organisms included in this group are : 



1. Staphlococcus pyogenes albus. 



2. Staphylococcus pyogenes aureus. 



3. Staphylococcus pyogenes citreus. 



4. Streptococcus pyogenes longus. 



5. Micrococcus tetragenus. 



6. Bacillus pyocyaneus. 



7. Bacillus pneumoniae. 

 and in certain special tissues 



8. Micrococcus gonorrhoeas. 



9. Microcoecus intracellularis meningitidis (Menin- 

 gococcus) . 



10. Micrococcus catarrhalis. 



11. Bacillus aegypticus (Koch- Weeks Bacillus). 



The group may with advantage be subdivided as 

 indicated in the following pages : 



