DISEASES COMMUNICABLE IN MILK 71 



supplying the infected milk, though in some instances the presence of sore 

 throat in the family of the proprietor raised the question whether these 

 throats bore any relation to the epidemic, and if so whether they were 

 the cause of direct infection of the milk, or of indirect infection by infecting 

 the udders, or whether they were not themselves derived from the cases of 

 garget in the herd. So the questions of whether the cow was infected by 

 humans and of the pathogenicity to man of the streptococci causative 

 of garget were raised. 



The investigations and experiments of Savage in England, of Ruediger, 

 and of Davis and Capps in this country were important in helping to 

 solve these questions, for, taken together, they indicated that the strepto- 

 coccus, which is ordinarily the cause of garget, is not pathogenic for man, 

 that the blood agar plate may be used to distinguish St. lacticus from 

 St. pyogenes, which is found in human throats, and that cows cannot be 

 infected with streptococci of human origin by smearing them on the 

 udder, but that they may be, either by abrading the teat slightly near the 

 teat canal and applying the cultures, or by injecting them a short dis- 

 tance into the udder. 



Study of Smith and Brown. Theobald Smith and J. H. Brown studied 

 hemolytic streptococci associated with outbreaks of milk-borne tonsillitis 

 in five Massachusetts cities, and compared them with those isolated in 

 other epidemics. They point out that mammitis is a disease that is due 

 to injury and subsequent infection of the udder and that it is prevalent 

 at all seasons of the year, whereas septic sore throat prevails mostly in 

 the transition period between winter and spring when throat affections 

 in man are common, and furthermore that in septic sore throat outbreaks 

 due to milk, the milk remains infected for a long time. They suggest that 

 the grafting of human streptococci on the udder in milking and in other- 

 wise manipulating the udder, and their subsequent development therein 

 afford a reasonable explanation of outbreaks of the disease. There is no 

 evidence that the streptococci that are responsible for garget are the oc- 

 casion of outbreaks of septic sore throat but it is conceivable that in 

 an inflamed udder both bovine and human streptococci might be found, 

 in which cases the latter should be regarded as an added infection. 

 The observations of Smith and Brown and of others indicate that when 

 infections of the udder with human streptococci do occur, physical mani- 

 festations in the udder are very slight if noticeable at all. 



As a result of their research these two investigators isolated two strep- 

 tococci that they held responsible for septic sore throat. One, outbreak 

 A, was altogether singular, in that the fermentations it produced with 

 sugars were different from those produced by streptococci that caused 

 the other outbreaks which they studied. These latter proved to be 

 identical with the streptococci that caused all the epidemics investigated 

 by others. 



