CHRONIC MAMMITIS. 581 



The lesions can easily be recognised on microscopic examination, 

 and, when the section is suitably stained, numerous streptococci can 

 be detected in the acini, which are blocked with proliferating epi- 

 thelial cells. These lesions are due to the invasion of colonies of 

 micro-organisms, which spread from below upwards. 



The streptococcus causing this mammitis colours readily with 

 thionin and methylene blue. It can be cultivated in liquid and 

 solid media containing sugar or glycerine, but growth is impeded by 

 the presence of peptone or common salt. Under ordinary circum- 

 stances the culture dies after some weeks, but if the acidity of the 

 medium is neutralised by the addition of powdered carbonate of 

 lime, it preserves its vitality for six or eight months. The culture 

 when injected into the udder of a healthy cow or she-goat reproduces 

 the disease. The micro-organism is not pathogenic for any of the 

 smaller animals used for purposes of experiment. 



Diagnosis and prognosis. The diagnosis is easy, the presence of 

 the sclerotic nodules being characteristic, whilst in doubtful cases a 

 microscopical examination can ahvays be made. 



The treatment should be prophylactic and curative. 



Prophylactic treatment comprises disinfection of the milkers' hands, 

 w^hich are the ordinary vehicles of contagion, and disinfection of the 

 cow's udder. Diseased animals in a byre should be milked last of all, 

 and the milk should be destroyed. 



Curative treatment is confined to local antiseptic injections. Warm 

 concentrated boric solution gives good results. The injections may be 

 repeated three or four times a day after milking, the liquid being left 

 for a certain time within the udder. In this way animals suffering 

 only from a slight attack may be cured, but when the disease is 

 already somewhat advanced injections lose their effect. 



Injections of fluoride of sodium (*! to '5 per cent, strength) 

 appear to be much more effectual. Moussu claims to have cured by 

 this means several old- standing cases where all four quarters of the 

 gland were diseased. 



These injections necessitate the same precautions as those above 

 indicated for securing perfect asepsis. In grave cases it is very diffi- 

 cult to prevent the disease from extending in infected stables, because 

 the necessary precautions cannot be observed. 



CHRONIC MAMMITIS. 



Chronic inflammation of the udder may form a termination of 

 ordinary acute mammitis, or it may result from infection with or- 

 ganisms of a less virulent type. 



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