and Laboratory Methods. 2181 



These results, whilst agreeing with Ford's, are not sufficiently authoritative 

 to allow us to assert positively that the bacteria found in the udders of the two 

 cows came from the blood or lymph stream, rather than through the teat, but in 

 conjunction with the results obtained by Ford, they throw doubt on the supposi- 

 tion that all udder infection comes originally through the orifice of the teat. It 

 is also noteworthy that a spore bearing bacillus belonging to the subtilis group, 

 and several micrococci were isolated by Ward from udder tissue. Another fact 

 which is difficult to explain, and which may possibly have some influence on the 

 bacterial content of the normal udder, is the strong germicidal power of freshly 

 drawn milk. This property was first noticed by Fokker ('2'!), and subsequently 

 confirmed by de Freudenreich (23), and quantitative studies of freshly drawn 

 milk inoculated with various bacteria showed that an actual destruction of bac- 

 teria took place. This germical property has been shown to exist in the milk 

 serum, and is evidently allied to the similar bactericidal property of blood, for 

 Brieger and Ehrlich (24), and Wassermann (25) have found that the milk of 

 immune animals can confer immunity. 



If then this germicidal power exists in fresh drawn milk, it is certain to be 

 present whilst the milk is still in the udder, and may inhibit or prevent the rapid 

 multiplication of adventitious bacteria, which penetrate up the opening of the 

 teat. Although we have frequently found large numbers of lactic acid bacteria 

 in freshly drawn milk, yet the reaction of this milk is never acid, but usually 

 amphoteric to litmus. 



De Freudenreich has also shown that the bactericidal power is not the same 

 for all species, that whilst the cholera vibrio, the typhoid bacillus, and even B. 

 Schafferii (a colon bacillus) are destroyed in large numbers, the bactericidal 

 action is less pronounced on lactic acid bacteria. These facts may possibly 

 explain why the germs of the Colon type are so seldom found in the healthy 

 udder, for we know that the teats and udder of the cow^ are constantly brought 

 in actual contact with particles of manure, and even the hands of the average 

 milker are soiled with stable filth, which undoubtedly contains Colon bacteria. 



It might be reasonably asked if the advice, commonly given to those who 

 wish to procure milk as near sterile as possible, to milk the first few streams on 

 the ground, is good. And in reply we would say decidedly yes, for not only is 

 the number of bacteria in the fore milk much in the excess of the bacteria found 

 in the rest of the milk, but frequently the number of species found in the fore 

 milk is considerably larger than that in the after milk. 



In reviewing the subject, there can be no doubt that the number of bacteria 

 present in the milk as it exists before being drawn from the udder is somewhat 

 startling, and were nothing more than an enumeration of the germs given there 

 might be some occasion for alarm. 



However, a systematic study of the germs proves that with the possible ex- 

 ception of rare cases, this source of bacterial life is much more beneficial than 

 baneful to the average consumer of milk and its products. 



Ontario Agri. College. F. C. HARRISON, 



M. CUMMINO. 



