PUS-PRODUCING MICROORGANISMS 93 



clothing, and utensils from patients with streptococcus 

 infections, because, despite the low resistance of the 

 organism, transmissions take place quite easily, and 

 it is highly probable that it always occurs by direct 

 transference of the germs as they live a very short 

 time exposed to light and air. This is particularly 

 true of puerperal infections, which are commonly the 

 result of infection with bacteria of high virulence. 

 This germ, unlike the staphylococcus, cannot infect 

 through the undamaged skin, demanding a wound for 

 its entrance. Streptococci vary in virulence and 



FIG. 27. Streptococcus pyogenes. (Abbott.) 



when the particular family of germs happens to be 

 very virulent, a single coccus may transmit an infection. 

 In diagnosticating streptococcic infections it is 

 necessary to make smears on glass slides and cultures 

 in appropriate media. The germs are found to be very 

 small single cocci varying from 5-^,7017 to ^ido of an 

 inch, dividing only in one plane and therefore growing 

 in chains. They are unable to move of themselves, 

 stain well by most methods, multiply best at 37 C. 

 (98 F.), but also at lower temperatures, and grow as 

 very delicate gray colonies. They have no effect upon 



