376 MILK AND MILK PRODUCTS 
surprising that the majority of udder bacteria should be of the same 
type as those common on the skin and mucous membranes of man and 
animals. The majority of the staphylococci on the skin are of the non- 
virulent variety which fails to produce pigment and fails to ferment 
mannite. But pathogenic varieties are also found on the skin where 
they ordinarily cause no trouble. . . . Whatever the variety may be, 
conditions in the udder are favorable to multiplication and frequently, 
large numbers are eliminated in the milk.” Rogers and Dahlberg 
(1914) in studying the origin of streptococci in milk decided that they 
were ‘contributed by the feces; infected udders and the animals’ mouths 
were also mentioned. Licking of the flanks and udders allow the bac- 
teria to reach the milk. Sherman (1915) found 19 out of 142 cows from 
6 different herds that gave a milk with over 10,000 bacteria per cubic 
centimeter. ‘T'wo of them had a bacterial content of 100,000 bacteria 
per cubic centimeter in their fresh milk. Sherman states that all of 
the cows were in a normal healthy condition but he does not state what 
data were secured to arrive at this conclusion. In 48 cows, in which 
there were no indications of disease, there were streptococci in the milk 
of 15. He regards the streptococci of milk as of little significance, 
which is a very interesting statement in light of the work on septic sore 
throat. Colwell (1917) studied the influence of high count and gargety 
cows on the number of bacteria in milk. Seventy-two per cent of the 
cows examined produced a milk with less than 10,000 bacteria per cubic 
centimeters. The other 28 per cent were classed as high-count animals. 
An interesting fact’ was established that, where one or more of the 
quarters were infected with an organism, the same organism could be 
isolated from the other quarters. Such data have much significance in 
the question of the relation of milk to septic sore throat ; it points out 
that all of the milk from an animal with an infected udder must be 
excluded from the milk supply. 
From the literature which has beeen presented above, it will be seen 
that some difference of opinion exists about the udder flora. The pre- 
dominating organisms seem to be micrococci and, as Evans pointed out, 
may come from the cow’s body. These enter the teat and reproduce 
since they are in a favorable environment. With regard to high-count 
cows too little information is available to definitely understand them. 
They are excluded from certain herds when certified milk ig being pro- 
duced. No exacting study is usually made to determine whether they 
are really healthy. If nothing is outwardly the matter with them, they 
are usually considered healthy without any other examination. It is 
possible that the large numbers of bacteria in the milk of certain cows 
