290 THE PYOGENIC COCCI 
dermally, has been reported.^ The toxin is most potent after six to 
eight days' incubation. 
Pi(7???e??/.— Staphylococci isolated directly from severe inflammations 
usually produce a golden-yellow pigment, but prolonged cultivation 
upon artificial media may result in a partial or complete loss of chro- 
mogenesis. These may occur as spontaneous variants:- also, Neu- 
mann^ has isolated non-chromogenic strains of staphylococci directly 
from typically chromogenic cultures by the plate method. The yellow 
pigment, which is produced most abundantly in media containing 
carbohydrates (particularly on potato) in the presence of free oxygen, 
appears to lie between the indi\'idual organisms, not within their sub- 
stance. It is insoluble, or nearly so, in water, but readily soluble in 
alcohol. It is related to the lipochromes. The pigment can be saponi- 
fied readily, and it evolves an odor of acrolein when it is dry-heated. 
Strong acids, notably sulphuric, change the yellow color to a green- 
blue (lipocyanin) . Lugol's solution (iodine-potassium iodide) turns it 
green. 
Enzymes. — I. Proteolytic— 0\d sugar-free broth and gelatin cultures 
of staphylococcus contain a proteolytic enzyme which will liquefy 
gelatin— a gelatinase. This enzyme is said to be obtained in an active 
state free from bacteria by filtering either broth or liquefied gelatin 
cultures of the organism through unglazed porcelain.^ An enzyme 
which liquefies casein is demonstrable in milk cultures; whether the 
latter enzyme is identical with the gelatinase has not been determined. 
2. .imylojytic.— According to Buxton,^ staphylococci produce a 
maltase which hydrolyzes maltose; no other inverting enzymes have 
been observed. 
3. Lipolytic— ^Ne\h and Corper^ have demonstrated a lipase of 
moderate activity in autolyzed agar slant cultures of staphylococci. 
4. Hemolytic— Many cultures of staphylococci are hemolytic when 
they are isolated directly from lesions upon blood-agar plates. Xeisser 
and Wechsberg,^ and Wechsberg^ have shown also that old (seven- to 
fourteen-day) broth cultures of staphylococci, particularly the more 
virulent strains, contain a soluble enzyme which hemolyzes blood both 
in vivo and in vitro. In litro this enzyme, staphylolysin, appears to 
digest the stroma of red blood cells, liberating hemoglobin from them. 
A quantitative measure of the activity of this hemolysin can be made 
by adding gradually decreasing amounts of broth culture (filtered 
through unglazed porcelain) to well-washed red blood cells suspended 
in salt solution; the mixtures are incubated at 37° C. for one hour, then 
J Parker, Hopkins and Gunther: Proc. Soc. Exp. Med. and Biol., 1926, 23, 344. 
2 Eisenberg: Centralbl. f. Bakteriol., orig., I Abt., 1906, 40, 188. 
3 Arch. f. Hyg., 1897, 30, 1. 
* Loeb: Centralbl. f. Bakteriol., 1902, 32, 471. 
5 Am. Med., 1903, 6, 137. 
6 Jour. Infec. Dis., 1912, 11, 388. 
' Ztschr. f. Hyg., 1901, 36, 299. 
8 Centralbl. f. Bakteriol., orig., 1903, 34, 849. 
