MAMMITIS. 
807 
it is merely hoped to offer here a few old ideas from what may 
possibly be to some of you a new vantage ground and perchance 
renew an interest in an old and important theme in the work of 
the every-day veterinarian. 
For our purposes we shall look upon mammitis as wound 
infection, not theoretically, though that is frequently the case, 
but practically. The “ wound ” consists of the delicate lacteal 
cells lining the alveoli, the more protective and older of which 
are shed at the period when mammitis is most prone to occur, 
leaving a surface little less resistant against infection than a 
real wound ; the orifice in the teat serves to maintain commun¬ 
ication with the exterior, and the milk within the gland, milk 
sinus or cistern, represents in our plan the blood or lymph 
poured out into the wound cavity, acting as a foreign body and 
serving as a nidus for bacterial multiplication, upon which the 
living, bactericidal tissues can exert but little influence. We 
shall enter into no argument as to the correctness of this view, 
since this is not essential to our purpose. 
Upon this hypothesis mammitis may be caused by any of the 
known pathogenic micro-organisms capable of causing wound 
infection in the ordinary technical sense, such as the various 
pus-forming streptococci, staphylococci and bacilli, with the 
occasional addition of special forms like actinomyees and bacilli 
tuberculosis. So far as known any bacteria capable of inducing 
wound infection is alike competent to produce mammitis, and 
conversely any of the micro-organisms found in mammitis are 
probably capable of infecting wounds. 
Viewing the mammary glands of domestic animals as seats 
for wound infection they offer interesting variations and resem¬ 
blances in the different species. As in other organs mammi¬ 
tis occurs more frequently as the milk producing qualities are 
intensified by breeding or feeding, so that it is observed most 
commonly in ruminants (cow, goat, ewe), and far more fre¬ 
quently in the dairy than in the beef cow. 
We have suggested that the milk retained in the udder 
might be compared to blood or lymph extravasate in a wound, 
