I 82 AGRICULTURAL BACTERIOLOGY. 



From these sources bacteria find their way into the milk 

 during the milking. In order to facilitate the milking there is 

 commonly used a milking vessel with a wide mouth and this, 

 of course, greatly facilitates the collection of bacteria. In a 

 one-test case it has been found that bacteria fell into the milk 

 pail at the rate of 3,250 bacteria per minute for an area of ten 

 inches, and in another as many as 1,210 per second for an 

 area with a diameter of three inches. For the purpose of 

 avoiding the bacteria from these sources various special means 

 have been suggested, such as special shaped vessels with nar- 

 row mouths, and special covers which filter the milk. For this 

 purpose, too, artificial milking machines have been invented, 

 which, by the use of a series of tubes, draw the milk directly 

 from the cow into the milking vessel without allowing any 

 exposure to the air. Great things were expected of these 

 milking machines, but they have hitherto proved of no prac- 

 tical value for the purposes designed, and they can at present 

 be regarded as nothing more than scientific toys. Indeed, so 

 far as experiment has shown anything thus far, it has indicated 

 that these machines increase rather than decrease the number 

 of bacteria ; a fact due doubtless to the difficulty of keeping 

 such apparatus properly clean. What may be the future of 

 such contrivances cannot of course be predicted, but at pres- 

 ent they are of no practical value. 



CONTROL OF THE NUMBER OF BACTERIA. 



Cleanliness. Thus the first practical method suggested for 

 reducing the number of bacteria, and hence for avoiding the 

 troubles which they produce in milk, is scrupulous cleanliness, 

 directed first toivard the cow, second toward the milk vessels, 

 third toward the milker and, incidentally, to the air of the cow 

 stall. In addition to this, all abnormal milk should be thrown 

 away, since such milk is almost sure to have come from dis- 

 eased udders which are filled with various pathogenic bacteria. 



