190 INFLAMMATION AND SUPPURATION 



of softening or breaking down of the vegetations occurs, and the 

 emboli thus produced act as the carriers of infection to other 

 organs, and give rise to secondary suppurations. 



Experimental. Occasionally ulcerative endocarditis is produced by the 

 simple intravenous injection of staphylococci and streptococci into the 

 circulation, but this is a very rare occurrence. It often follows, however, 

 when the valves have been previously injured. Orth and Wyssokowitsch 

 at a comparatively early date produced the condition by damaging the 

 aortic cusps by a glass rod introduced through the carotid, and after- 

 wards injecting staphylococci into the circulation. Similar experiments 

 have since been repeated with streptococci, pneumococci, and other 

 organisms, with like result. Blbbert found that if a potato culture of 

 the staphylococcus aureus were rubbed down in salt solution so as to 

 form an emulsion, and then injected into the circulation, ^some minute 

 fragments became arrested at the attachment of the chordae tendinese and 

 produced an ulcerative endocarditis. 



Acute Suppuratiye 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 

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

 great 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 peri- 

 osteum 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 



