PATHOGENIC BACTERIA. 



285 



marked in a specific way which sometimes form pus, as the 

 bacilli of diphtheria, tuberculosis, glanders and typhoid fever. 

 Frequently two or more species of pyogenic bacteria will be 

 found associated. 



The table below, quoted from Dowd, shows the frequency 

 of the occurrence of various pyogenic bacteria in 135 cases of 

 different types of suppuration. 



Streptococcus pyogenes alone 



Streptococcus pyogenes predominant 



Streptococcus pyogenes relatively few 



Staphylococcus aureus alone 



Staphylococcus pyogenes aureus predom- 

 inant 



Staphylococcus pyogenes aureus relatively 

 few 



Staphylococcus pyogenes or epidermidis 

 albus alone 



Staphylococcus pyogenes or epidermidis 

 albus predominant 



Staphylococcus pyogenes or epidermidis 

 albus relatively few 



Staphylococcus cereus albus 



Staphylococcus citreus 



No growths on agar 



Very few growths on agar 



Bacillus pyocyaneus 



Bacillus coli communis 



Overgrown 



Few undetermined colonies 



9 



3 

 ri 



13 



4 

 12 







I 

 II 



3 

 3 

 3 

 I 



5 



The condition of the animal's tissues is of great importance 

 in determining whether or not suppuration will occur when 

 they are exposed to infection. It will be seen that we are re- 

 peatedly subjected to infection with pyogenic bacteria, but that 



