THE STAPHYLOCOCCUS GROUP 289 
The organisms are aerobic, facultatively anaerobic. Tlie opti- 
mum temperature of growth lies between 28° and 38° C.; growth 
ceases below 8° C. and above 43° C. 
Staphylococci are among the most resistant of the non-sj)()re-f()rni- 
ing bacteria to physical agents. An exposure of one hour at 80° C. 
or two hours at 70° C. moist heat is usually fatal. Several minutes' 
exposure at 100° C. (flowing steam) or twelve hours' exposure to direct 
sunlight may fail to kill them. Indirect daylight may fail to destroy 
their vitality even after two weeks; three months' continuous drying 
(on cloth or paper) is equally ineffective; 0.1 per cent mercuric chloride 
and 5 per cent carbolic acid usually kill the naked germs in about 
ten minutes. 
Fig. 36.— Staphylococcus. X 1000. 
Products of Growth.— Acids, chiefly lactic, acetic and formic, but with 
demonstrable amounts of propionic, butyric and valerianic, are formed 
during the fermentation of ordinary sugars. No gas is produced. The 
pus of staphylococcus abscesses is usually acid in reaction; the organisms 
appear to form limited amounts of acid from protein. ^ It is probable 
that some of the acid is derived from a carbohydrate-like radical in 
the protein molecule.'^ Emmerling^ has identified indol, phenol, skatol 
and trimethylamine among the decomposition products of staphylo- 
cocci grown anaerobically in protein media. Cacace"* has shown that 
the earlier decomposition products produced from gelatin and coagu- 
lated blood serum are chiefly proteoses and peptones; as proteolysis 
proceeds, these products are degraded to simpler amino-acid com- 
pounds. 
Toxin.— k soluble toxin, which causes necrosis in rabbits when 
0.1 to 0.3 cc. of the bacteria-free filtrate from proteose peptone broth 
cultures grown in a 10 per cent atmosphere of COo is injected intra- 
1 Kendall, Day and Walker: Jour. Am. Chem. Assn., 1913, 35, 1246. 
- Kendall and Farmer: .Jour. Biol. Chem., 1912, 12, 215. 
3 Ber. d. deutsch. chem. GeselLsch., 1896, 29, 2721. 
* Centralbl. f. Bakteriol., 1901, 30, 244. 
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