354 Bureau ok Farmers' Institutes. 



the creamery and took the milk as they found it — in ordinary 

 condition — they found an average of 200,000 bacteria in half a 

 teaspoonfu] of milk. A healthy cow, under normal conditions — 

 if you can get the milk from her udder and not have it exposed 

 to the air — is said to he practically sterile; i. e., if I could take a 

 sterilized tube and insert it into a healthy cow's udder, and draw 

 the milk from it through that sterilized tube into a sterilized bot- 

 tle, so that no air could come in contact with it, that milk would 

 keep almost indefinitely. 



The most trouble that comes to the milk is from the outside. 

 Of course, if your cow eats leeks and turnips — some of those 

 foods which have a strong smell — then that strong-smelling suit- 

 stance, in the process of digestion, is taken in by the breath and 

 into the lungs and so taken into the circulation — you get a smell 

 in the milk. But you don't want to confuse the smell with the 

 great majority of troubles in the milk. "When we understand 

 that most of these troubles come from outside sources; that bac- 

 teria are dropping into the milk when exposed to the air, and, in 

 most barns, under ordinary conditions, the air is full of them, we 

 can readily see that the resultant product, under the most careful 

 management later on, is sure to show the bad effects of such con- 

 tamination. 



I would not have you understand that all these little plants 

 make trouble for us. If thev did, the chances are that we should 

 fail, no matter how well the work was done. 



There is one of them we must have in order to make good but- 

 ter and good cheese; that is the one that produces the lactic acid. 

 You know you can't make a desirable product "without it. We 

 always get this acid when we expose the milk for a short time. 

 The germ works in the sugar of the milk and the product is lactic 

 acid. The other thing that We get in the milk that doesn't work 

 on sugar, but does on the albumen and casein, is the one that 

 makes the gas. You take a sample of butter and smell it. At 

 first you do not detect anything special; but, as you smell a little 

 more, you detect a flavor of stale grease. That comes from the 

 fact that some of these germs, working on the nitrogen compounds 

 of the milk, have affected the fat and given it that old grease 

 smell. 



When you handle your milk in a way that some of these germs 

 get in, you must expect to have trouble with the product. It 

 doesn't make any material difference if there are only a few of 

 them, and when they increase with the rapidity which ordinarily 



