ACUTE SUPPURATIVE PERIOSTITIS. 167 



fevers, but in a great many cases the path of entrance is 

 quite obscure. That the organisms enter frequently by a 

 small surface lesion, and are carried by the blood stream to 

 the part affected, there can be no doubt. In the course of 

 this disease they are always very liable to follow serious 

 secondary infections, such as small abscesses in the kidneys, 

 heart-wall, lungs, liver, 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 bone 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 con- 

 ditions 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 of the periosteum, before the organ- 

 isms 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 in the human subject in its typical 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 



