112 MASTITIS OF THE COW 



actinomycomata may become swollen, softened and disin- 

 tegrated and finally be discharged into the milk. In this 

 manner the ray fungus can: (1) be discharged into the 

 milk; (2) be spread to other parts of the same quarter by 

 leucocytes; (3) stagnate in the milk-ducts together with 

 softened necrotic parts of the actinomycoma. 



Genuine milk-infection [parenchymatous mastitis^ 

 does not appear to occur ; that is the stagnated fungus does 

 not induce necrosis of the subjacent epithelium, at least not 

 to any marked degree. Formation of croupous membranes 

 does not appear to occur in this condition. 



Ulceration of a Blood-vessel Wall. — This is pos- 

 sible, of course, but only appears in exceptional cases and 

 with the relative inf requency of actinomycosis of the lungs. 



Ulceration Through the Skin. — I have not ob- 

 served this condition in any of my cases. It is possible, 

 however, like the not uncommon ulceration of the skin in 

 actinomycosis of the jaw. It is certainly very infrequent 

 in the udder, nevertheless. 



types 



Depending upon the ports of infection the following 

 types are distinguished : ( 1 ) primary udder-actinomycosis, 

 (a) by infection through the teat canal, (b) by infection 

 through wounds; (2) secondary or embolic udder-actino- 

 mycosis. 



These types have the same general differential char- 

 acteristics as the previously described types of pyobacillosis 

 (see Pyobacillosis). 



Primary udder-actinomycosis following teat-infection 

 is the most common type. The foci are so distributed in 

 the udder that one cannot expect to find an anatomical 

 difference from the embolic type upon post-mortem exam- 

 ination. The condition almost always begins in one quar- 

 ter, but may frequently be spread to other quarters by 



