STAPHYLOCOCCUS PYOGENES. 163 



remain white, or when transplanted a white growth may 

 become yellow. 



Vitality: The staphylococcus is an exceedingly tenacious 

 germ, retaining its vitality for a long time under the most 

 adverse circumstances. It is rapidly killed by exposure to 

 live or streaming steam and by a 3 per cent, solution of car- 

 bolic acid. Sutures contaminated by the staphylococcus are 

 sterilized in one minute by a 3 per cent, solution of formal- 

 dehyde. 



Pathogenesis : All the staphylococci cause local suppurative 

 inflammations, and exhibit but little tendency to spread. 

 Occasionally they are the cause of fatal septicaemia or pyaemia, 

 especially when they find their way directly into the blood or 

 lymph-current, or when the process is very virulent and 

 accompanied by rapid absorption of the poisonous products 

 of the germs. 



These cocci usually gain entrance into the body through an 

 abrasion of the skin or mucous membranes. Infection of 

 the ducts of the glands in the skin results in the formation 

 of a carbuncle or a furuncle. It is said that infection cannot 

 occur unless the skin is broken, and yet infection may occur 

 through an unbroken mucous surface, as in staphylococcus 

 sore throat. Staphylococcus infection is not a very serious 

 affair, because of the tendency of the process to remain 

 localized. 



The staphylococci are found in all abscesses (except in cold 

 abscesses, which are sterile) and phlegmons, impetigo, ecthyma, 

 acute suppurative inflammations of the nose, throat, and 

 mouth, empyema, tonsillar abscess, phlyctennlar conjunctivi- 

 tis, suppurative inflammations of the middle ear, pelvic 

 abscess, and generally in all those conditions that are described 

 as localized suppurations, and in the mixed infections. 



Staphylococcus pyogenes aureus : This is the most common 

 and also the most virulent of the staphylococci. It is con- 

 sidered the type of the group. It is also called the golden 

 coccus, because of the beautiful golden or orange pigment 

 which it produces in culture. It is always found in the pus 

 of acute abscesses. 



Staphylococcus pyogenes albus : So far as its appearance and 



