124 MILK AND THE PUBLIC HEALTH ch. vi 



condition of true vaccinia was present in the cows, as well as what 

 he considers to be the virus causing the outbreak. 



V. There is also another fact, which may or may not be 

 germane to this subject, but which is very interesting. If the 

 records of milk-borne outbreaks of septic conditions, and especially 

 scarlet fever, are carefully studied, it will be found in a considerable 

 number of them (when the condition has been looked for) that teat 

 ulceration, mastitis, or other local lesions of the milk organs, have 

 been found to be present. This is inclusive of epidemics in which 

 a definite human source of infection has been traced and accepted 

 as a sufficient cause of the outbreak, and where no question of 

 bovine infection has been raised. The writer is of opinion, from 

 his personal experience, that the proportion of cows with ulcerated 

 teats is decidedly higher in the herds of cows from farms implicated 

 in milk epidemics of scarlet fever than for ordinary farms. This 

 higher incidence of lesions may be accidental, but it would seem 

 more probable that a relationship exists, and that the sore teats 

 are not infrequently a nidus for passive infection. That is, given 

 a human milker, actively or passively harbouring scarlet fever 

 organisms, he may, or may not, infect the milk suppl}^, but is more 

 likely to do so if the infection is in the first place- conveyed to 

 ulcerated teats, and in this way infects the milk. For one thing, 

 the dose is likely to be larger, and also decidedly less intermittent. 



