Some farmers have great difficulty in delivering milk once a day and having it sweet when it arrives at the plant. We have kept a bottle of certified milk for more than three weeks in a refrigerator where the temperature is above forty degrees and at the end of that time it had not turned sour. Such results can be only obtained by experts, but it is not difficult to become expert enough to always be able to sell milk that is in a good marketable condition, delivered once a day. =Cooling Milk.= The growth of bacteria in milk depends a great deal upon its cooling. Milk has a great tendency to take up bad odors, and its tendency to do this depends upon its temperature. Milk should be cooled within thirty minutes after it is drawn from the cow. If cooled below seventy degrees immediately and kept at that temperature or below, there will be very little difficulty of milk souring, provided due care has been taken regarding sanitation and cleanliness. Well water temperature in this climate is usually fifty-four degrees. By pumping fresh water through a tank, having it overflow so that the warm water will flow off, it is easy in a short time to get milk as low as sixty-five degrees. When running water is not available, it is better to stir the milk until it is as cold as it will get in such water as you have, then set the cans in a small tank of fresh water that can be pumped by hand if necessary. Many farmers use the stock tank to cool the milk in first, then use some half barrels cut off at a height so that the water can not overflow into the milk but that it will stand slightly higher than the milk in the cans. Use one half-barrel for each can of night’s milk. In the morning cool the milk in the tank only. However, the most satisfactory arrangement would be to have a small engine with which fresh water may be pumped at milking time, and let the milk tank overflow into the stock tank until the milk is cooled and the tank is full of cold water. A tank should be divided by partitions made of slats running up and down so that a can partly filled may float without tipping over. It is not absolutely necessary that milk be uncovered while it is being cooled, but the cover prevents the milk from cooling as rapidly. Remember that warm water always rises. The cold water will be at the bottom of the tank. Some farmers divide their milk so that the cans will all float. The milk warms the water and the warm water rises above the level of the milk in the cans. Milk should always be covered when left sitting by the road waiting for the hauler, and should always be covered in the wagon or truck. Wet the blanket or canvas that covers the milk. This helps to keep it cool. CHAPTER XI. EXPERIMENTS BEING TRIED OUT ON OUR DAIRY FARM.