PERIOSTITIS, OSTEOMYELITIS, ERYSIPELAS. 199 



cocci into the circulation. Similar experiments have since been repeated 

 with streptococci, pneumococci, and other organisms, with like result. Ribbert 

 found that if a potato culture of the staphylococcus aureus were rubbed down 

 so as to form an emulsion in salt solution, and then injected into the circula- 

 tion, some minute fragments became arrested at the attachment of the chordae 

 tendineae and produced an ulcerative endocarditis. 



Acute Suppurative Periostitis and Osteomyelitis. Special 

 mention is made of this condition on account of its comparative 

 frequency and gravity. The great majority of cases are caused 

 by the pyogenic cocci, of which one or two varieties may be 

 present, the staphylococcus aureus, however, occurring most 

 frequently. Pneumococci have been found alone in some cases, 

 and in a few cases following typhoid fever, apparently well 

 authenticated, the typhoid bacillus has been found alone. In 

 others again the bacillus coli communis is present. 



The affection of the periosteum or interior of the bones by 

 these organisms, which is especially common in young subjects, 

 may take place in the course of other affections produced by 

 these organisms or in the course of infective fevers, but in a 

 gr~at many cases the path of entrance cannot be determined. 

 In the course of this disease serious secondary infections are 

 always very liable to follow, such as small abscesses in the 

 kidneys, heart wall, lungs, liver, etc., suppurations in serous 

 cavities, and ulcerative endocarditis ; in fact, some cases present 

 the most typical examples of extreme general staphylococcus 

 infection. The entrance of the organisms into the blood stream 

 from the lesion of the bone is especially favoured by the arrange- 

 ment of the veins in the bone and marrow. 



Experimental. Multiple abscesses in the bones and under the periosteum 

 may occur in simple intravenous injection of the pyogenic cocci into the 

 blood, and are especially liable to be formed when young animals are used. 

 These abscesses are of small size, and do not spread in the same way as in 

 the natural disease in the human subject. 



In experiments on healthy animals, however, the conditions are not 

 analogous to those of the natural disease. We must presume that in the 

 latter there is some local weakness or susceptibility which enables the few 

 organisms which have reached the part by the blood to settle and multiply. 

 Moreover, if a bone be experimentally injured, e.g. by actual fracture or by 

 stripping off the periosteum, before the organisms are injected, then a much 

 more extensive suppuration occurs at the injured part. 



Erysipelas. A spreading inflammatory condition of the 

 skin may be produced by a variety of organisms, but the disease 



