CHEMISTRY. 25 



tlirowu out of the crucible. This operation requires from 20 to 30 min- 

 utes. The fusion is cooled and treated with 1(>0 to 150 cc. of boiliug 

 water and 50 cc. of concentrated hydrochloric acid, the solution being 

 kept near the boiling point until the mass is dissolved. The solution 

 is evaporated to dryness on the water bath, and thel)oric acid removed 

 by evaporating on a water bath at 75 to 80'^ (). with 2 to 4 successive 

 portions of GO to 75 cc. each of methyl chlorid, prepared as needed by- 

 saturating metliyl alcohol in the cold with dry hydrochloritsacid gas. 



Note on the distinction betv/een boiled and unboiled milk. 

 E.UBNER {Hyg. Bundschau, 5, No. 22; ahs. in Ztschr. Fleisch- und Milch- 

 liijg., {1^9(1), No. 3, p. ~)2). — The author states that the methods for 

 distinguishing between heated or boiled and raw milk are not entirely 

 reliable. Schreiner has claimed that boiled milk did not give otf any 

 hydrogen sulphid on heating, as fresh milk did; but the author did not 

 notice the evolution of hydrogen sulphid in the case of many samples 

 of normal milk. Likewise guajac tincture, which usually gives a blue 

 color with raw milk, was not found reliable. 



The author recommends the following test: Milk is shaken with more 

 common salt than it will dissolve, heated to 30 to 40° 0., and filtered. 

 If coagulated albumen separates in the filtrate on heating, the conclu- 

 sion is that the sample was boiled milk or a mixture of raw and boiled 

 milk. 



It is suggested that the change in milk by cooking, noticeable in the 

 taste and smell, may be due to a breaking up of constituents, as in the 

 case of the extractives of meat. 



Rapid methods for butter examination, Ostektag {Ztschr. Fleiseh- 

 und Milehhyg., 6 {1896), No. 2, pp. 72-7i), Jigs. 2). — The advantages of 

 reliable rapid methods for testing the purity of* butter are discussed, 

 and the methods of Jahr and Bischoff are described in detail. 



Jahr's method iucludes 3 tests, i. e., heating (1) in a water bath at 

 50° C. with water; (2) with sulphuric acid, hydrochloric acid, and potas- 

 sium-permanganate solution; or (3) with common salt solution, hydro- 

 chloric acid, and iJotassium-])ermanganate solution. Treated in either 

 of these ways, pure butter, oleomar'garine, and mixtures of the two give 

 characteristic reactions, either in the appearance of the fat or coloring. 



An apparatus for making the test is illustrated and described. As 

 the (juantities to be used of some of the reagents are stated in terms 

 of the graduates furnished with the apparatus, no clear idea is fur- 

 nished of the amounts actually used. 



The Bischoff test depends ui)on the appearance of the sample when 

 melted under specific conditions in an apparatus provided for that pur- 

 l)ose, which is figured. The test is said to be used otticially in Berlin, 

 and by the veterinary police in the country. 



The determination of small amounts of magnesia in limestone, Ukrzkklu aud 



F(ii!STi:i: (Ztschr. Biibenz. Ind., 46 {1S9G), p. 2S5 ; aha. in Chem. Zttj., W {189G), No. 42, 

 liepert., p. 154). 



