BREEDING DAIUY CATTLE 233 



by releasing the pressure allow the milk to run down to the 

 17.6 c.c. mark. Place the point of the pipette into the test- 

 bottle neck, holding both pipette and bottle at an angle, then 

 remove the finger to allow the milk to flow into the bottle. 

 To be sure that every drop i^ out of the pipette blow through 

 it into the test-bottle. The sampling should be done in dupli- 

 cate to make sure of the results. 



Using the acid. — Much care should be exercised not to 

 spill the sulfuric acid on the hands, clothing, or floor. Should 

 any be accidentally spilled, pour on plenty of water, then add a 

 little lime or baking soda. Always keep water and lime at 

 hand for this purpose. 



After all the samples of milk to be tested have been meas- 

 ured, the acid should be added. To do this, fill the acid meas- 

 ure to the 17.5 c.c. mark and gradually pour into the test- 

 bottle, hpldjpg the bottle in a slanting position. By turning 

 the bottle'the acid will carry down all particles of milk left in 

 the long neck. Hold the bottle by the neck and give it a cir- 

 cular motion for a few moments, thus mixing the milk and acid 

 until no milk or clear acid is visible. The contents of the 

 bottle should be dark colored and hot. Do not allow the bottle 

 to stand too long before mixing or the test will not be clear. 



Whirling the bottles. — The bottles and machine should be 

 hot ; and if not a steam machine, use boiling water to warm up 

 the machine. Place the bottles in the machine so that each 

 will have another directly opposite to keep the machine in 

 balance. Whirl five miiiutes. Then stop, and with the pipette 

 or cup with small spout, add hot water to each bottle until the 

 contents come up to the bottom of the neck. Whirl two 

 minutes. Add hot water sufficient to bring the top of the fat 

 nearly to the top of the graduation on the neck of the bottle. 

 Whirl one minute. The fat should form a clear column free 

 from black or white patches in the neck of the bottle. 



Reading the percentage of fat. — Keep the fat warm. Hold 



