320 TEXT-BOOK OF BACTERIOLOGY. 



tube will disturb the bacterial masses and cause a transitory cloudi- 

 ness of the bouillon. 



Erysipelas can be reproduced from such artificial cultures in 

 susceptible animals. Fehleisen, and many others after him, have 

 performed successful transmissions to man for a particular pur- 

 pose, surgical practice having often shown a striking improvement 

 in malignant tumors which could not be operated upon (especially 

 sarcoma and carcinoma), and whenever the tumors came within 

 reach of erysipelas arising from some other cause, they improved. 

 This experience was utilized by attempting an artificial production 

 of the curative erysipelas; the results have been rather beneficial. 



Among animals, mice are usually completely refractory to sub- 

 cutaneous applications, while rabbits prove susceptible. After in- 

 oculation at the ear, there arises a progressive, erysipelatous, in- 

 flammatory swelling, rapidly spreading from the point of infection, 

 but usually not going beyond the ear and subsiding in a short time. 

 Suppuration and a severe general sickness with rise of tempera- 

 ture, etc., and even death occur only in young animals. A direct 

 introduction of cocci into the blood current will produce no disturb- 

 ance. 



The experiments with erj^sipelas cocci present the same result 

 that was observed with Fraenkel's pneumonia bacteria and the 

 diphtheria bacilli : the virulence of the micro-organisms is unstable 

 from the beginning, even if taken up directlj' from the diseased 

 tissue (their natural habitat), and succumbs more or less rapidly to 

 natural weakening in our artificial cultures. The varying degree 

 of original virulence is certainly significant as to the character and 

 progress of isolated cases, and the general subsequent decrease 

 of the infectious force accounts for the differences in the results of 

 experiments with animals. 



We know that the cocci just described are the original exciters 

 of erysipelas, and we must again turn to the question as to the 

 manner in which the micro-organisms enter the bodj' and their 

 infiuence upon it. 



It is certain that, in the great majority of cases, infection com- 

 mences froiji lesions which are sometimes scarcely visible, and from 

 wounds of the integument having in some way come in contact 

 with streptococci. The Conditions of this mode of transmission 

 have as yet been but little investigated. We presume, but cannot 

 assert on the strength of reliable facts, that in this case we have 

 an accidental infection by micro organisms, largely diffused in the 

 outside world, rather than a direct infection of a healthy individual 

 by a sick one. 



