New York AGRICULTURAL EXPERIMENT STAaTIon. 349 
USE OF OTHER ACIDS AND ALKALIS. 
Other alkalis (hydroxids of barium and calcium) and other 
acids (hydrochloric and sulphuric) were employed in develop- 
ing the test but were not found to give satisfactory results. 
In the Matthaiopoulos method, sulphuric acid is used. The 
special advantage of dilute acetic acid, as compared with the — 
other acids tried, lies in its smaller dissolving and absorbing 
properties for casein.® 
MODIFICATIONS FOR USE OF CHEMISTS. 
Instead of using 17.5 cc. (18 grams) of milk, and the special 
strength of solutions indicated, it may be found more con- 
venient in chemical laboratories to use 20 cc. of milk and 
tenth-normal solutions of acid and alkali. In such cases, the 
method is carried out in the usual manner and the percentage 
of casein calculated by the following formula. 
~— B X 1.0964 = per ct. of casein. 
By using 22 cc. of milk and tenth-normal acid and alkali, 
the formula becomes 
A : 
— — B = per ct. of casein. 
2 
Each cubic centimeter of standard solution corresponds to 
one per ct. of casein in milk under these conditions, 
USES OF CASEIN TEST. 
A simple method for determining casein in milk can be 
utilized to advantage under a variety of conditions, and we 
will briefly consider some of the principal opportunities for 
its application. 
———— 
poe ACT, xpt. ota, secn. Bul. No; 3. 
