294 THE PYOGENIC COCCI 
following manner: The organism is isolated on agar slants in pure 
culture, washed off, after twenty-four hours' incubation, in normal salt 
solution, thoroughly emulsified, and standardized so that each cubic 
centimeter contains the requisite number of bacteria. They are killed 
either by heating to 80° C. for one hour, or, better, by the addition of 
0.5 per cent carbolic acid, and incubation at 37° C. for twenty-four 
hours. The sterility of the culture must be demonstrated before it is 
used. This vaccine is inoculated subcutaneously, with surgical pre- 
cautions, using the dosage mentioned above as a routine. The inocula- 
tions are repeated at intervals of from three to five days. The duration 
of the immunity induced by vaccination is not known. Vaccines are 
less effective in pyemia and metastatic staphylococcus infections than 
in the localized infections. 
The lessened lipase activity of the blood, manifested by a decreased 
splitting of ethyl butyrate, is a frequent result of staphylococcus 
invasion, according to Clerc;^ according to V. Dungern,- the blood 
serum from cases of extensive osteomyelitis is several times as inhib- 
itory to the staphylococcus enzymes as is that of normal individuals. 
Antibodies.— The cell substance of staphylococci does not appear 
to be very poisonous to experimental animals,^ and although an anti- 
staphylolysin and an antileukocidin are produced relatively easih' 
in experimental animals, they do not appear to confer any considerable 
degree of immunity. Agglutinins do not appear to have been demon- 
strated in the blood serum of man and animals suffering from staphylo- 
coccal infections, but Kolb and Otto, and Proscher^ claim to have 
prepared sera of marked agglutinating value, which clump virulent 
strains in higher dilution than non-virulent strains. Parker'' has been 
able to induce antibody formation to the soluble toxin of the staphylo- 
coccus, best by intradermal infections. 
Precipitins.— Specific precipitin reactions appear to have been 
demonstrated in animals infected with staphylococci. 
Bacteriological Diagnosis. — (a) Microscopic— A Gram stain of the 
suspected material usually suffices to establish a diagnosis. It must 
be remembered, however, that staphylococci from pus and exudates 
may occur in pairs and even in short chains; they may, therefore, 
be mistaken for streptococci. An absolute diagnosis can be made 
only by the identification of pure cultures. 
(6) Chdtv ml. — Fure cultures of staphylococci are usually obtained 
readily by "streaking out" or plating the organisms on agar. Blood- 
agar is preferable, if streptococci or pneumococci are also suspected 
to be present, otherwise the latter may be overlooked. The identi- 
fication of the colonies on agar usually can be made by the examina- 
tion of a Gram-stained preparation. Staphylococci are common on 
1 Compt. rend. Soc. de biol., 1901, 53, 1131. 
2 Milnchen. med. Wchnschr., 1898, 45, 1040. 
3 Kruse: Allgemeine Mikrobiologie, Leipzig, 1910, p. 968. 
* Centralbl. f. Bakteriol., orig., 1903, 34, 437. 
6 Jour. Exp. Med., 1924, 40, 761. 
