CHEMISTRY. 561 



the Station for 1893 (E. S. K., 0, p. 960) a description is given of the 

 deteiniination of casein in milk. In the method here described for 

 determining' albumen tlie filtrate from the determination of casein with 

 acetic acid is digested in a boiling water bath until the albumen coag- 

 ulates and settles to the bottom, leaving the supernatant liquid clear. 

 Ten or 15 minutes is said to usually sutiiee for this. The nitrogen is 

 determined iu the washed precipitate by the Kjeldahl method, and the 

 amount of nitrogen multiplied by the fiictor 6.25 gives the albumen. 



To determine the eftect of continued digestion, trials were made in 

 which the solution was digested for from 5 minutes to 10 hours. The 

 conclusions from these trials were as follows: 



"(1) In one case lieatiug for 5 minutes gave low results; in two other cases, good 

 results. 



"(2) Iu general, the results varied little with increased length of time of heating. 



"(3) There was a slight tendency to higher results with increased length of heat- 

 ing, bnt such increase was more or less irregular and at most amounted to only 

 0.002 or 0.003 per cent of nitrogen. 



"(4) It would, therefore, appear that entirely satisfactory results can be obtained 

 by heating the solutioii containing albumen under the given conditions for 10 or 15 

 rainntes, while au increased length of time of heating does not practically change 

 the results. 



"It may be stated that the precipitate formed always filters readilj' and washes 

 easily." 



A brief summary is given of the method employed by the author for 

 the separation and determination of the different nitrogenous com- 

 pounds of cows' milk based on the method as described. 



Potassium chromate as a milk preservative, J. Froidevaux 

 {Jour. Fharm. et Chint., ser. 6, 16 (ISOd), pp. 155-158 ; abs. in Analyst, 

 21 {1896), ^^oi\,x>. ^^<55).— The author finds that at least 0.2 gm. of neutral 

 potassium chromate per liter is necessary for preserving milk apprecia- 

 bly, and this amount gives the milk an abnormal color. For the detec- 

 tion of chromates in milk the method of Denigos (addition of 1 cc. of 

 2 j)er cent silver uitrate to 1 cc. of milk) is satisfactory where over 

 0.01 gm. per liter is present. The following method is preferred: Dis- 

 solve the ash from 10 cc. of milk in a few drops of water acidified with 

 nitric acid, neutralize with magnesium carbonate, and add silver nitrate 

 (preferably a 20 per cent solution). Another test given is as follows: 

 Dissolve the ash from 10 cc. of milk or water acidulated with sulphuric 

 acid, and add tincture of guaiacum little by little. An intense blue color 

 which rapidly disappears is produced when chromates are present. The 

 reaction is said to detect 0.02 to 0.03 gm. of chromate per liter. 



Report of the chemist of South Carolina Station, M. B. Hardin 

 {South Carolina l^ta. lipt. 1S05, pp. 51-6.!). — Analyses are given of 

 cottonseed meal, "brewery feed,'' "corn chops," sugar beets, sweet 

 potatoes and millet seed for starch, acid phosphate tloats, Pamunkey 

 phosphate, Florida i)liosphate, muriate of potash, suli)hate of potash, 

 kainit, mixed fertilizers, water, phosphate rock, wood ashes, ores, and 

 minerals. 



