292 Wound Infection; Suppuration 



occurs rapidly, as in the incubator, it exceeds the rapidity of 

 color-production, so that the center of the growth is dis- 

 tinctly colored, the edges remaining white. 



Potato. Upon potato the growth is luxuriant, Staphylo- 

 coccus 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 cloudiness, with a small quantity of slightly yellow- 

 ish 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 followed 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 

 of alcohol upon staphylococci, prepared an acicular crystal- 

 line body soluble in alcohol and ether, but slightly soluble 

 in water, to which he gave the name phlogosin. 



Mannatti found that pus has substantially the same toxic 

 properties as sterilized cultures of the staphylococcus ; that 

 repeated injections of sterilized pus induce chronic in- 

 toxication and marasmus; that injection of sterilized pus 

 under the skin causes a grave form of poisoning; and that 

 the symptoms and pathologic lesions caused by these 

 injections correspond with those observed in men suffering 

 from chronic suppuration. 



Van de Velde * found that the staphylococcus has some 

 metabolic products destructive to the leukocytes, which 

 he has called leukocidin. This poison causes the cells to 

 cease ameboid movement, become spheric, and gradually 

 to lose thin granules, until they finally appear like empty 

 sacs containing shadow nuclei, which eventually disappear. 

 The leukolysis occurs in about two minutes. These ob- 

 * " La Cellule," xi, 1896, p. 349. 



