32 



cylinder or jar 1 1 inches by 2 inches, (4) Mann's acid test- outfit, (5) 

 Farrinj^^ton's alkaline tablet test outfit, (6) Wisconsin curd test outfit, 

 and (7) rennet extract. 



1. Use of lactometer. — (Reference No. 3, pp. 113-114, or No. 12, 

 pp. S()-98.) Use both Quevenne and New York State^ forms of 

 lactometers. The lacto-thermometer forms are preferable. (1) Test 

 lactometers in water at different temperatures. (2) Do the same in 

 milk and whey. (3) Calculate per cent of total solids in different 

 samples of milk from lactometer reading and per cent of fat. Cal- 

 culate per cent of solids-not-fat. 



2. Action of acids and alkalis on each other. — Add 1 cubic centimeter 

 of sulphuric acid to 100 cubic centimeters of water and mix by shak- 

 ing. Then dissolve 5 alkaline tablets in 85 cubic centimeters of water. 

 Take 20 cubic centimeters of the dilute sulphuric acid in a teacup and 

 add to it 5 drops of solution of phenolphthalein. Then add the alkali 

 solution gradually, shaking after each addition and continuing until 

 the pink color remains instead of disappearing on shaking. Then add 

 1 cubic centimeter of dilute acid and note the disappearance of color. 

 Add more alkali until color reappears. What chemical change takes 

 place when the alkali is added to the acid? Does the acid combine 

 with the alkali? Is the acid all combined with acid wjien the pink 

 color appears ? Do acids form color with phenolphthalein ? Do alka- 

 lis form color with phenolphthalein ? (Reference No. 3, p. 111.) 



3. Mann's acid test. — (Reference No. 3, p. 112, or No. 12, p. 96.) 

 Carry out details of Mann's acid test with (a) milk, (b) whey, exam- 

 ing them at intervals of an hour. 



4. Farrington's alkaline tablet test. — (Reference No. 3, p. 112, or 

 No. 12, p. 99.) Use this test in same manner as preceding. 



5. Monrad rennet test. — (Reference No. 3, p. 67, or No. -8, p. 38.) 

 Apply the test as described to the same milk at intervals of thirty 

 minutes for two or three hours, letting milk stand at temperature of 

 80° to 85° F. 



6. Marschall rennet test. — (Reference No. 3, p. 68, or No. 8, p. 39.) 

 Apply to same milk at intervals of thirty minutes, letting milk stand 

 at temperature of 80° t:o 85° F. 



7. Wisconsin curd test. — (Reference No. 3, ]). 64, or No. 8, p. 15.) 

 Apply this test to milk of different herds of cows, noticing whether 

 there is any relation between the results and the cleanliness of the 

 stables in the case of the individual herds. 



8. Hot-iron test. — Prepare cheese curd with rennet and test from 

 time to time on hot iron (references No. 3, p. 74, and No. 8, p. 61). 



