104 EXPERIMENT STATION RECORD. 



This and subsequent operations must be carried out in an atmosphere 

 absolutely free from ammonia. As soon as the formation of crystals 

 on the surface of the solution is observed it is allowed to cool, and then 

 again slowly evaporated to 5 cc. After cooling, 20 cc. of 90 i^er cent 

 alcohol is added and the solution is allowed to stand for a long time 

 with stirring. The crystalline precipitate is brought on to a filter which 

 has been previously washed with 80 per cent alcohol and hot water, 

 washed with 80 per cent alcohol, dried in a Eofi'meister drying oven at 

 110°, and weighed. 



Tests of this method on pure sulphate, of potash and mixtures of 

 sulphate of potash with other salts gave results which agreed closely 

 with the theoretical percentage of potash. 



A method for determining the purity of butter by means of its 

 density, E. Beulle {Compt. Rend., 122 {1896), No. 6, p. 325 ; Rev. 

 IScieni., ser. 4, 5 {1896), No. 8, p. 217; Jour. Agr., 1896, Mar. 7 ; ahs. 

 in Milch Ztg., 25 {1896), No. 19, p. 297). — According to the abstract 

 experiments showed that when the water, casein, and coloring matter 

 were removed, the exact determination of the specific gravity of the 

 fat remaining gave very reliable indication of the relation between the 

 pure butter and the foreign fats added. 



Estimation of uric acid by Fehling's solution, E. Eiegleb, 

 {Ztschr. anaJyt. Cheni., 35 {1896), No. l,p.31). — The method depends on 

 the formation of cuprous oxid wlien ati alkaline solution of uric acid is 

 boiled with Fehling's solution, an average of 0.8 gm. copi^er correspond- 

 ing to 1 gm. uric acid, the extremes in 10 experiments being 0.7812 and 

 0.8333 gm. The method is described in detail. — b. w. kilgore. 



Further notes upon the fats contained in the tuberculosis 

 bacilli, E. A. de Schweinitz and M. Dorset ( Centhl. Bald, und Par. 

 Med., 19 {1896), No. 18-19, pp. 707, 70S). — This reports a continuation of 

 analyses of the tuberculosis bacilli, published by the same authors in 

 1895.1 ^ mass of dried tuberculosis bacilli weighing about 3..5 gm. was 

 collected and submitted to examination. The crude fat, constituting 37 

 per cent of the whole, was saponified in a closed flask by means of 

 sodium hydrate, and the acids freed with sulphuric acid. The volatile 

 fatty acids were removed by distillation, the 3.5 gm. of crude fat giving 

 only 0.05 gm. of volatile fatty acids. They had an odor resembling 

 tbat of sweet almonds. The non-volatile fatty acids were partly soluble 

 in 85 i)er cent alcohol and the remainder in absolute alcohol. By 

 means of fractional crystallization an acid melting at 62° C. was obtained 

 and identified as palmitic acid. The acid soluble in hot 85 per cent 

 alcohol was purified by repeated crystallization and showed a melting- 

 point of 102° C, which would indicate a liigher carbon content than 

 any acid heretofore noted in plants. The acid soluble in cold 85 per 

 cent alcohol melted at 42 to 43° C. and is believed to be lauric acid. The 

 work is being continued. — m. Dorset. 



'Jour. Am. Chem. Soc, 1895, Aug. 



