SUPPURATION. 189 zone of furuncles. Bockhart suspended a small portion of an agar-agar culture in salt-solution, and scratched it gently into the deeper layers of the skin with his finger- nail; a furuncle developed. Bumnv injected the coccus suspended in salt-solution beneath his skin and that of several other persons, and produced an abscess in every case. The Staphylococcus aureus is not only found in the great majority of furuncles, carbuncles, abscesses, and other inflammatory diseases of the surface of the body, but also plays an important role in a number of deeply- seated diseases of the internal organs. Becker and others obtained it from the pus of osteomyelitis, demonstrating that if, after fracturing or crushing a bone, the Staphylo- coccus was injected into the circulation, osteomyelitis would result. Numerous bacteriologists have demon- strated its presence in ulcerative endocarditis. Rodet has been able to produce osteomyelitis without previ- ous injury to the bones; Rosenbach was able to produce ulcerative endocarditis by injecting some of the staphy- lococci into the circulation in animals whose cardiac valves had been injured by a sound passed into the carotid artery ; and Ribbert has shown that the injection of cultures of the organism may cause the valvular lesion without the preceding injury. The Staphylococcus aureus is an easy organism to ob- tain, and can be secured by plating out a drop of pus in gelatin or in agar-agar. Such a preparation, however, generally does not contain the Staphylococcus aureus alone,, but shows colonies of the Staphylococcus albus as well. In addition to these two principal forms, one sometimes discovers an organism identical with the pre- ceding, except that its growth on agar-agar and potato is of a brilliant lemon-yellow color, and its pathogeny for animals much less. This is the Staphylococcus citretts of Passet. It is not quite so common, and not so patho- genic as the others, and consequently much less im- portant.