1902-3.] Bacterial Contamination of Milk. 483 



his clothes, and invariably wash his hands immediately before milking. 

 The milking smock should be washed frequently and should be kept, not 

 in the open barn or stable, but in some place as far removed as possible 

 from all kinds of dust and dirt. The practice of moistening the hands 

 or cow's teats with milk should be scrupulously avoided. 



Milking Machines. 



Of late years several milking machines have been introduced to 

 obviate the difficulty in obtaining milkers, and to lessen the time taken 

 in milking. Such machines, in order to be a success, must do the 

 milking naturally, quickly, thoroughly and without any annoyance to 

 the cow. Further, milk drawn by such a machine must be of good 

 keeping quality, and the machine must be adaptable to the requirements 

 and arrangements of an ordinary dairy farm. 



When first introduced many dairymen expressed the opinion that 

 these machines would guard against the admittance of all dirt, but 

 unfortunately this requirement has not been fulfilled by a machine 

 installed in the Dairy Stable of the Ontario Agricultural College.^* This 

 machine, called the " Thistle Milking Machine," {see Fig. 7), was in more 

 or less constant use in our stable during the summer of 1899, and we 

 took advantage of this opportunity to make bacteriological analyses of 

 the milk milked with the machine as compared with milk drawn by 

 hand milking. We found that the machine milk had a far larger germ 

 content than that milked in the usual manner, and after making a direct 

 comparison between the number of bacteria in machine milk and the 

 number in hand milk, we found that the proportion varied greatly, from 

 three to twenty times as many bacteria being found in the machine milk 

 as in the hand drawn milk. The averages were as follows : — 



Machine Milk. Hand Milk. 



No. of Analyses. No. of Bacteria No. of Analyses. No. of Bacteria 



in c.cm. of in c.cm. of 



morning's milk. morning's milk. 



161 141,600 78 10,600 



Evening's Milk. Evening's Milk. 



74 165,000 16 12,900 



These results were greatly in favour of hand-milking, and the large 

 number of bacteria found in machine milk was attributed to three 

 causes : 



