386 Bacteria in Relation to Country Life 



barn comparatively free from bacteria, more or less 

 considerable numbers of them will still remain suspended 

 in the air, and will fall into the milk at the first favor- 

 able opportunity. It will be seen that much will depend 

 on the character of the farm. 



It is self-evident that the larger the surface of the 

 milk exposed, the greater will be the number of bacteria 

 to fall into it in a given time. This circumstance has 

 therefore, stimulated attempts to eliminate, as far as 

 possible, the exposure of the milk to the air. With 

 thorough care in the cleaning of the various parts of 

 the milking-machine, the germ content of freshly drawn 

 milk may be materially diminished. Not only is it 

 necessary to clean the parts of the machine very thor- 

 oughly, but, also, to free the air entering it from bacteria 

 by means of cotton placed in the tubes. With such 

 precautions observed, the milk drawn by the machine 

 is much superior to that drawn by hand; in fact, in 

 some instances, it is almost germ-free. It will be seen, 

 therefore, how much depends on the operator. 



These excellent results cannot be secured, however, 

 until all the rubber tubes are placed, after thorough 

 washing, in a 3.5 per cent solution of formalin, and the 

 air entering the machine drawn through a layer of 

 cotton. When these precautions are not observed, the 

 germ content of the machine-drawn milk is generally 

 higher than that of the hand-drawn milk. In fact, it 

 has been demonstrated that the thorough sterilization 

 of the rubber tubes by formalin is not sufficient for 

 making the germ content of the machine-drawn milk 

 lower than that of the hand-drawn milk. The cotton 



