80 Wilk and Its Products. 
readily be detected by the senses of smell or taste, 
Farrington’s alkaline tablets offer a very convenient 
means of selecting milks that are suitable or un- 
suitable for pasteurizing purposes. For this purpose 
it is convenient to make the tablet solution (see 
Chap. vu.) by dissolving one tablet in each ounce 
of water, or one tablet in 30 ec. «. of water. Then 
with a cup or other convenient vessel and a small 
measure of any suitable size, the comparative acid- 
ity of different milks can be readily and quickly de- 
termined as follows: Put a measure full of milk 
into the cup and add two measures of the tablet 
solution. If the color disappears, more than .2 of 1 
per cent of lactic acid is present, and the milk is too 
sour for pasteurizing purposes. If the milk remains 
pink, less than .2 of 1 per cent of lactic acid is pres- 
ent, and the milk may be safely used. If it is 
desirable to measure the amount of acid, each meas- 
ure of solution may be roughly taken to represent 
-l1 of 1 per cent of acid. Thus, if the pink color 
remains when one measure of the solution has been 
added, the milk contains .1 per cent of acid. If it 
require four measures of the solution before the pink 
color is permanent, the milk contains .4 per cent of 
acid. A convenient measure for this purpose is made 
by soldering a piece of stiff wire to the side of a 
No. 10 cartridge shell, after the manner of a milk- 
measuring dipper. 
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