23'6 DOMESTIC ANIMALS, DAIRYING, ETC. 



on a brick or a piece of sheet lead. Liquids containing sulphuric 

 acid should not be thrown where live stock can come in contact with 

 them, but can be safely poured into an earthen jar or into a clay 

 drain tile set on end in the ground. The sulphuric acid bottle should 

 be kept stoppered because the acid readily absorbs moisture from the 

 air and thus becomes weakened. Always add acid to milk in the 

 bottle, never add milk or water to the acid. 



Sulphuric acid will quickly eat holes in the clothing and cause 

 blisters on the skin, and the greatest care should be taken not to spill 

 it. To observe its effect, put a drop or two of acid on each of two 

 pieces of paper, or cotton or woolen cloth. With a little water, rinse 

 the acid as quickly as possible off one piece, and note whether it is 

 spotted where the acid fell. Leave the other piece for a few hours 

 and then wash it. 



When handling sulphuric acid wear an apron and have a sup- 

 ply of water ready for washing spilled acid off of the clothing, person 

 or furniture quickly in case of an accident. After thorough wash- 

 ing with water, a little household ammonia, or baking soda or lime 

 water may be applied and washed off with more water. Sulphuric 

 acid must not be measured in the pipette because of the danger of 

 drawing it into the mouth. 



Mixing the Acid and Milk. The sulphuric acid in the test bot- 

 tle weighs more than the milk, and the acid goes to the bottom at 

 once, forming a clear layer, which soon becomes brown where it 

 touches the milk. As soon as the acid is all poured in, the test bottle 

 should be held by the neck and shaken in a circle so as to mix the 

 acid and milk. Keep the liquid out of the neck of the bottle, while 

 shaking it, to prevent loss. During the filling and mixing point 

 the neck of the bottle away from the face, so that no drop of acid 

 may be thrown into the eyes. 



As the shaking is continued, the mixture turns to a uniform 

 brown color and becomes quite hot. Be sure to mix thoroughly. 

 Write the number of the sample with a common black lead pencil 

 on the roughened spot on the side of the test bottle. 



With the same precautions as before, transfer a pipette full of 

 milk from the other sample bottle to a second test bottle; measure 

 in the acid, and mix by shaking. If the test bottles become cold after 

 adding acid and before whirling, they should be warmed again by 

 placing in water at about 160 degrees for about 15 minutes. While 

 the bottles are hot put them into the tester and whirl them as di- 

 rected below. 



Whirling the Bottles. Having placed the bottles opposite each 

 other in the whirling machine (called a centrifuge) and closed the 

 cover, turn the handle for four or five minutes at the speed indicated 

 by the directions furnished with the machine. Allow it to stop of its 

 own accord. 



The centrifuge is generally enclosed in an iron box so that if 

 any thing should break while the machine is running, no one is 

 injured by the flying pieces. The cover should always be kept closed 

 while the machine is running. The wheels will turn easier and last 



