MILK 253 



churning of cream, it is evident that the product of an elaborate sub- 

 sequent process, a process entirely foreign to the manufacture of 

 butter, should be designated by a distinctive name. 



How to Distinguish Genuine Butter from Renovated, and Both 

 from Oleomargarine. Several of the States have already enacted 

 laws requiring the distinctive branding or labeling of the new product 

 when offered for sale, and as a consequence chemists have, during the 

 last year or two, devoted considerable study to methods for distin- 

 guishing between the genuine and the renovated article. One of the 

 results of such study is the method of Hess and Doolittle, which is 

 based upon the difference in the relative proportions of albumin and 

 so-called casein, as well as the different properties of the latter, exist- 

 ing in the two products. But as this is distinctly a laboratory method, 

 quite inapplicable in the household, it will not be dwelt upon here. 



Another useful method, of the nature of a preliminary test, is 

 that of microscopic examination by polarized light, with and with- 

 out the selenite plate ; but for the reason just stated, this, too, will be 

 passed with a bare mention. So also with .various chemical tests and 

 the regular chemical analysis of the fats. 



Household Tests. Another important means employed in dis- 

 tinguishing between genuine and renovated butter is the boiling test. 

 This test was first mentioned in scientific literature by Dr. Henry 

 Leffmann, who states that it was shown to him by a Mr. Morris, a 

 detective in oleomargarine prosecutions. It has been in use about ten 

 years, and was originally used only for the detection of oleomar- 

 garine ; but after the advent of renovated butter the test was found 

 to serve almost equally well in distinguishing this product from gen- 

 uine butter. Therefore, this test distinguishes between genuine but- 

 ter on the one hand and oleomargarine and renovated butter on the 

 other; and, fortunately, it is so simple of execution that it can be em- 

 ployed in any kitchen almost as well as in the laboratory, and re- 

 quires no special skill on the part of the operator. It consists merely 

 in boiling briskly a small portion of the sample and observing its 

 behavior the while. 



In the kitchen the test may be conducted as follows: Using as 

 the source of heat an ordinary kerosene lamp, turned low and with 

 chimney off, melt the sample to be tested (a piece the size of a small 

 chestnut) in an ordinary tablespoon, hastening the process by 

 stirring with a splinter of wood (for example, a match). Then, in- 

 creasing the heat, bring to as brisk a boil as possible, and after the 

 boiling has begun, stir the contents of the spoon thoroughly, not neg- 

 lecting the outer edges, two or three times at intervals during the 

 boiling always shortly before the boiling ceases. In the laboratory 

 a test tube, a spoon, or sometimes a small tin dish, is used in making 

 this test. From the last-named utensils the test is often called the 

 "spoon test," and sometimes the "pan test." 



A gas flame, if available, can be used perhaps more conveniently 

 than a kerosene lamp. Oleomargarine and renovated butter boil 

 noisily, sputtering (more or less) like a mixture of ^grease and water 

 when boiled, and produce no foam, or but very little. Renovated 



