ERYSIPELAS. 187 



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 arrangement 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. If, however, a bone be 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 maybe produced by a variety of organisms, but the disease 

 in the human subject in its characteristic form is almost 

 invariably due to a streptococcus, as was shown by Fehleisen 

 in 1884. He obtained pure cultures of the organism, and 

 gave it the name of streptococcus erysipelatis ; and, further, 

 by inoculations on the human subject as a therapeutic 

 measure in malignant disease, he was able to reproduce ery- 

 sipelas. As stated above, however, one after another of the 

 supposed points of difference between the streptococcus of 

 erysipelas and that of suppuration has broken down, and it 

 is now generally held that erysipelas is produced by the 

 streptococcus pyogenes of a certain degree of virulence. It 

 must be noted, however, that erysipelas passes from patient 

 to patient as erysipelas, and purulent conditions due to 

 streptococci do not appear liable to be followed by erysipe- 

 las. On the other hand, the connection between erysipelas 

 and puerperal septicaemia is well established clinically. The 

 conditions which produce the special degree of virulence in 

 the streptococcus for the occurrence of erysipelas are not 

 yet fully known. 



