110 MILK 



In cow mastitis and some cases of teat ulceration the lesions 

 show streptococci in enormous numbers. In one instance the 

 writer found that when the cows of a cow-keeper whose fresh 

 milk contained enormous numbers of streptococci were examined 

 severe teat ulceration, associated with abundant streptococci, 

 was found upon several of the cows. 



The differentiation of the streptococci found in mixed milk 

 samples is scarcely sufficiently advanced to furnish reliable 

 guidance as to which varieties are prejudicial but such differ- 

 entiation is more valuable when dealing with samples from 

 individual cows. 



Mastitis, or garget, in cows may be due to a number of 

 different organisms, but in the writer's investigations 75 per cent, 

 of the cases were due to streptococci, while 80 per cent, of the 

 streptococci formed one common type, the Streptococcus mastitidis. 

 This is a long chain streptococcus, growing rapidly in broth, form- 

 ing a coherent deposit, but leaving the upper part clear. It grows 

 upon gelatine without liquefaction, produces acid in milk, and 

 clots it within three days, gives no neutral red reaction, and 

 produces acid in lactose and saccharose media, never in mannite, 

 and not usually in salicin, raffinose, or inulin. It is non- 

 pathogenic to mice. Inoculated into the teats of goats, it sets 

 up mastitis on the infected side 1 . 



In investigating human outbreaks of sore throat, etc., spread 

 by milk and associated with the presence of a cow with mastitis 

 in the herd supplying the milk the best way to establish or 

 confute any causal relationship is to promptly ascertain if the 

 streptococci from the human disease can cause mastitis in goats 

 by infection of the teats. If they are of milk origin they should 

 produce, if not mastitis, at least a marked inflammatory reaction 

 in the inoculated goat 2 . 



Summary of procedures recommended. 



A number of different methods have been discussed. For 

 the convenience of those not versed in the examination of milk 

 samples the following procedures are recommended : 



1 For detailed consideration of the bacteriology of mastitis see Local Govt. Board 

 Medical Officer's Report 1906-7, 1907-8. 



2 Local Govt. Board Medical Officer's Report 1908-0, 



