22 MILK 
Babcock’s formula has been much used in the 
United States. It is adapted to calculating the 
solids not fat. In this formula g is the entire 
figure for sp. gr. referred to water as 1. 
100 g— 
Suf = (sere 1) xa5 (100 — f) 
Babcock has also given a much simpler form 
adapted for total solids. This differs but slightly 
from Richmond’s. 
Total Proteins.—3 types of processes are 
employed for this estimation: Calculation from 
the total nitrogen; precipitation and direct 
weighing; calculation from the ‘‘aldehyde-figure.”’ 
Milk contains appreciable amounts of non- 
protein nitrogen, but the fact is usually disre- 
garded. According to Munk, this may range, in 
cow’s milk, from 0.022 to 0.034%, and from 
‘0.014 to 0.026% in human milk. By these 
figures, the average protein nitrogen in cow’s milk 
would be 94%, and in human milk 91%, of the 
total nitrogen. 
‘ Kjeldahl-Gunning Method.—(Calculation from 
total nitrogen). 
Reagents: 
Potassium sulfate—A coarsely powdered form 
free from nitrates and chlorids should be selected. 
Sulfuric acid.—This should have a sp. gr. 
1.84 and be free from nitrates and ammonium. 
