CHEMICAL TESTS AND ANALYSES 363 
Gravimetric Determination. 
Dilute a measured portion of a 40 per cent solution with an 
equal volume of water, use 5 c.c. of the diluted mixture, correspond- 
ing to 1 gram of the evaporated milk and proceed as directed under 
“Milk.” 
Ash. 
Ignite the total solids at very low redness, cool, weigh, see 
“Milk,” 
Proteids. 
Use 5 c.c. of a 40 per cent solution, determine nitrogen accord- 
ing to the Gunning method as directed under “Milk,” and multiply 
result by 6.38. 
Lactose. 
Dilute 10 grams of a 40 per cent solution to about 40 c.c. and 
add .6 c.c. of Fehling’s copper solution; nearly neutralize with 
sodium hydroxide, make up to 100 c.c., filter through dry filter, and 
determine lactose in an aliquot as directed under “Milk.” 
Fat. 
The Modified Babcock Method.' 
Carefully weigh 4.5 grams of well-mixed evaporated milk into 
the 8 per cent test bottle. Add one 17.6 c.c. pipetteful of water. Add 
17.5 c.c. of sulphuric acid and shake until the curd in the test bottle 
is completely dissolved. Whirl at usual speed (one thousand revo- 
lutions per minute) for five minutes. Mix equal portions of water 
and sulphuric acid in glass beaker. For one or two tests, one 
pipetteful of water and one acid measure full of acid are sufficient. 
Fill test bottle to slightly below the bottom of the neck with the hot 
diluted acid. Whirl for two minutes. If the fat collected at the 
base of the neck is not clear, shake the bottle until all the curdy 
matter is completely dissolved, fill the bottle to about the 8 per cent 
mark with hot mater, whirl for one minute and read the test at 135 
degrees F. The fat column must be read from the top of the upper 
meniscus to the bottom of the lower meniscus. Multiply the reading 
by 4. This gives the correct per cent of fat. 
Instead of weighing 4.5 grams into the test bottle, a 4.3 cc. 
1 Hunziker and Spitzer, Indiana Agricultural Experiment Station, Bulletin 
No. 134, 1909. 
