INFECTIOUS MASTITIS IN GENERAL 23 



an udder-infection. The leucocytes which are dangerous 

 to the saprophytes may be called back by the patho- 

 genic organisms, and then the saprophytes may develop 

 unhindered. 



They cannot attack living tissue, but the necrosis pro- 

 duced in the primary lesion constitutes an excellent culture 

 medium for them, and consequently undergoes putrefac- 

 tion. We may call this process exudative gangrene.^ 



These saprophytes are large, anaerobic, rod-shaped 

 putrefactive bacteria. 



A saprophytic invasion of this type may easily occur 

 in croupous mastitis, since a shred of fibrin can remain 

 hanging in a teat canal. A shred of this kind can then 

 become permeated by saprophytes which grow in and 

 through it, so that the shred may constitute a good bridge 

 for the infection. 



Following such a saprophytic invasion with exudative 

 gangrene, the milk becomes stinking, homogeneous and 

 thinly fluid, since the necrotic cells and the fibrin shreds 

 dissolve during putrefaction, and the leucocytes are killed 

 by the poisons of putrefaction. 



GENERAL CONDITIONS 



Blood-infection. — The primary lesion may be per- 

 meated with the growing pathogenic organisms, which 

 induce deep necrosis with destruction of the blood-vessel 

 walls, so that the bacteria may enter the vessel and produce 

 a generalized blood-infection or septicaemia. This second- 

 ary blood-infection, if not overcome by the defensive ele- 

 ments of the blood, can induce secondary lesions, as an in- 

 fectious pneumonia or arthritis. 



Death caused by an acute general blood-infection is 

 due to septic intoxication. The external symptoms of a 



^ These necrotic parts will be thrown off with the croupous 

 or diphtheritic exudate and constitute a part of that exudate. 



