INFECTIOUS MASTITIS 33 



which the stroma or fibrous tissue is iuvolved. The form of 

 mastitis more frequently encountered as an infectious (trans- 

 missible) disease is characterized by very marked changes in 

 the milk, accompanied by the usual symptoms of parenchymat- 

 ous inflammation of the gland itself. The discharge from the 

 udder usually contains flaky masses held in suspension in the 

 clear or perhaps cloudy serum. The color varies, and occa- 

 sionally the fluid is blood-stained. The microscopic examina- 

 tion shows the presence of agglutinated fat globules, pus cells 

 and often red blood corpuscles. 



A number of bacteria* considered of more or less etiologi- 

 cal value have been found associated with lesions of doubtful 

 specific origin. The results of Kitt, Nocard, Mollereau, Guille- 

 beau, Zschokke, Bang and still others, in which a Badermm, 

 a Bacillus, a Micrococcus, a Staphylococcus, and a Streptococcus 

 have been found and reported as standing in a causal relation 

 to the trouble, indicate that a variety of microorganisms are 

 active in producing those affections which are frequently 

 grouped without distinction as infectious mastitis. The review 

 of much of the literature on this subject shows that a number 

 of cases reported as infectious were isolated or sporadic ones, 

 /. e. , they were in dairies where the disease did not spread to 

 other animals. While these may be truly infectious in their 

 nature they should be differentiated from the rapidly spread- 

 ing phlegmons which are easily recognized as infectious 

 (^contagious). 



If we take into account the variety of anatomical changes 

 which have been described in the various udder affections, we 

 can reasonably admit that different agencies may have been 

 instrumental in their production. The various species of bac- 

 teria which have been isolated from the udder lesions mav verv 



*Among the bacteria which have been foi'.nd in udder trouble and 

 described as a possible or perhaps the more probable cause the follow- 

 ing species may be mentioned : Bacterium phlegmasia: uberis, Strep- 

 tococcus agalacticc conlagioscc. Staphylococcus inastitidis, Galactococcus 

 versicolor, G. fulvus, G. albus. 



