334 STATE BOARD OP AGRICULTURE. 



Acid. — 



The acid is sulphuric (H, SO^). To be of proper streng-th it should 

 have a specific gravity of 1.82. Sulphuric acid has a great aflfiuity 

 for water, so it is absolutely necessary that the acid container should 

 be kept tightly closed, otherwise the acid will take up moisture from 

 the air and thus be weakened. It should also be remembered that 

 sulphuric acid is very corrosive and must be handled with great care. 

 If it should get on the skin or clothing, wash off with water and then 

 treat with dilute ammonia. 



TESTING WHOLE MILK. 



The following are the various steps in testing whole milk : — 



1. Mix the sample of milk thoroughly at a temperature of 70° F. by 

 pouring from one vessel to another several times. 



2. Measure out 17.0 cc. of the sample with pipette. 



3. Transfer the milk from pipette to the whole milk test bottle. 



4. Measure out 17.5 cc. of acid at 70° F. and add to the milk in the 

 test bottle. 



5. Mix the milk and acid thoroughly with a rotary motion. 



6. Put bottles in tester and whirl 5 minutes at the proper speed. 



7. Add water at about 130° F. till the test bottle is filled to the neck. 

 S. Turn the machine one minute more and then fill the bottles up to 



about the 9% mark with warm water. 



9. Turn again one minute and tead at a temperature of about 

 130° -140° F. 



Mixing the Milk. — 



Fat rises to the surface very quickly if milk is undisturbed, hence it 

 is very essential that the milk should be thoroughly mixed to cause the 

 fat to be evenly distributed throughout. If this is not done the test will 

 not be accurate. In case the cream has hardened or sticks to the side 

 of the receptacle, the sample should be thoroughly warmed 'and then 

 mixed. 



Taking the Sample. — 



The 17.G cc. sample should be taken quickly after the mixing. This is 

 done by placing the lower end of the pipette well down in the milk and 

 withdrawing the air from the pipette by the mouth, thus allowing the 

 milk to enter the tube until it reaches a point somewhat above the mark 

 on the pipette. Then the forefinger is quickly placed over the upper end 

 of the pipette and the milk is slowly lowered to the mark by allowing 

 air to enter at the top. The amount of milk taken weighs 18 grams, 

 which is the weight of samples used in testing any dairy x^i'oduct. 



Transferring the Sample. — 



In transferring the sample to the test bottle, the pipette is held in a 

 slanting position so that the lower point rests against the inside of the 

 bottle's neck. 



111. 4, fig. 1), shows proper position of pipette and test bottle while put- 



