An Easy Method for Estimating the Protein Content of Milk

In the routine analyses of milk under the Food Adulteration Act, we find the specific gravity, fat and total solids, and our work is done. But the profession as well as the public may like to know the quantities of the other nutrients in the milk. Milk proteins are of as much importance from the biological point of view as the milk fat; if the latter contains the vitamines, the former contains the amino-acids which are essential for growth. The Kjeldahl process, the usual method for estimating the proteins, is not very suitable for routine work; they can be estimated fairly easily from the aldehyde figures by formol-titration methods, such as those of Steinegger or of Richmond and Miller. But the method which is the subject of this paper is similar to the one for estimating albumen in the urine by precipitating it with a reagent, it is exceedingly easy, and can be done by any medical man. We have many precipitants for proteins, and just as in the case of urine we get a fairly workable idea of the amount of albumen from the depth of the precipitate, so in the case of milk there is no reason why a method on the