346 



Suppuration 



present in Staphylococcus aureus. It is this precipitate in 

 particular that gives the organism its name, " golden sta- 

 phylococcus." 



Agar-agar. The growth of the golden Staphylococcus 

 upon agar-agar is subject to considerable variation in the 

 quantity of pigment produced. Sometimes, perhaps rarely, 

 it is golden; more commonly it is yel- 

 low, often cream color. Along the 

 whole line of inoculation a moist, 

 shining, usually well-circumscribed 

 growth occurs. When the develop- 

 ment occurs rapidly, as in the incu- 

 bator, it exceeds the rapidity of color 

 production, so that the center of the 

 growth is distinctly colored, the edges 

 remaining white. 



Potato. Upon potato the growth 

 is luxuriant, Staphylococcus aureus 

 producing an orange-yellow coating 

 over a large part of the surface. The 

 potato cultures may give off a sour 

 odor. 



Bouillon. When grown in bouillon 

 the organism causes a diffuse cloudi- 

 ness, with a small quantity of slightly 

 yellowish sediment. The reaction of 

 the medium is increasingly alkaline. 

 Nitrates are reduced to nitrites. 



Milk. In milk, coagulation takes 

 place in about eight days, and is fol- 

 lowed by gradual digestion of the 

 casein. 



Thermal Death Point. Staphylococci are usually quite 

 susceptible to the effect of heat, though their resistance is 

 not uniform. Sternberg found them destroyed by an 

 exposure to 62 C. for ten minutes, and to 80 C. for one 

 and a half minutes, but three cultures studied by von Lin- 

 gelsheim were not killed by an exposure to 60 C. for an 

 hour, and one culture studied by him endured an exposure 

 to 80 C. for ten minutes. 



Toxic Products. Leber seems to have first conceived of 

 suppuration as a toxic process depending upon the soluble 

 products of parasitic fungi, and in 1888, through the action 



Fig. 104. Staphylo- 

 coccus pyogenes au- 

 reus. Puncture cul- 

 ture three days old in 

 gelatin (Frankel and 

 Pfeiffer). 



