264 SPECIFIC MICRO-ORGANISMS 



is commonly a terminal phenomenon, but it may occur without 

 immediate fatal issue, and may result in endocarditis and strepto- 

 coccus arthritis. 



Immunity to streptococcus infection is slight in degree and 

 very temporary. Koch showed that erysipelas could be repeat- 

 edly produced on the same area of the skin by inoculation at inter- 

 vals of 10 to 12 days. Rabbits and horses acquire a high degree 

 of immunity when treated with gradually increasing doses of 

 many different strains of streptococci. The serum of such 

 animals has a marked protective influence when injected into 

 animals and has been employed in treating human infections, 

 in some cases with success, while in others the serum has appar- 

 ently exerted no influence on the course of the disease. In local- 

 ized chronic streptococcus infections, treatment with autogenous 

 bacterial vaccines (bacteria suspended in salt solution and killed 

 by heat) seems to produce favorable effects in some cases. 



Streptococcus Lacticus (Micrococcus Ovalis). This is a 

 variety of Streptococcus pyogenes growing normally in the intes- 

 tine and of special importance as the cause of the normal souring 

 of milk. 



Staphylococcus (Micrococcus) Aureus. By the early ob- 

 servers (Rindfleisch, Klebs) this organism was not distin- 

 guished from the streptococcus. Pasteur in 1880 obtained it in 

 broth cultures from pus. Ogston in 1882 clearly distinguished it 

 from the streptococcus. Rosenbach (1884) by his extensive inves- 

 tigations established the position of the Staphylococcus as a 

 cause of wound infection and of osteomyelitis. 



Staphylococci have their natural habitat on the skin, in the 

 mouth, in the nasal cavities and in the intestine, without the 

 presence of inflammation. More virulent forms occur in in- 

 fected wounds, furuncles, carbuncles, various localized purulent 

 inflammations, bacteremia (staphylococcemia), endocarditis, 

 osteomyelitis, meningitis and pneumonia. 



The cell is spherical, 0.7 to 0.9," in diameter. Division 

 takes place in various planes, giving rise to irregular bunches of 



