Febbuaby 19, 1909] 



SCIENCE 



307 



determination in milk products such as condensed 

 milk, evaporated milk, malted milk, milk powders, 

 milk chocolate, milk cereal products and candies 

 containing milk products or other fats. 



The new method suggested is so simplified as to 

 give correct results in the hands of chemists not 

 having special experience in the analyses of such 

 products, besides materially decreasing the time 

 of making analyses. A weighed quantity of the 

 product is dissolved in water or made into an 

 emulsion, the fat and proteids precipitated with 

 copper sulphate, filtered on a fat-proteid free 

 paper, allowed to drain and the damp precipitate 

 on the paper directly extracted with ether. The 

 extracted precipitate is used for making proteid 

 determination by the Kjeldahl method, digesting 

 paper and precipitate. Filtrate from the copper 

 sulphate precipitation is used for determination 

 of sugars and gums. If insoluble starch is pres- 

 ent, a weighed filter paper is used and starch 

 determined as difference between total weight of 

 precipitate and proteid and fat foimd. 



Carbohydrates such as starch, dextrines, gums 

 and sugars (cane, maltose, lactose and dextrose) 

 interfere with complete extraction of fat with 

 solvents and in the separation of the fat by the 

 modified Babcock method. Drying the milk 

 product for extraction, direct and after soaking 

 in water, will give low results, due to change in 

 fat during drying (Gudeman, Proceedings A. 0. 

 A. a., 1902). 



The analyses of milk products containing sugars 

 or cereals or gums are not accurate and it is 

 recommended, therefore, to confine such analyses 

 to the determination of water, ash, fats, proteids, 

 soluble carbohydrates, insoluble carbohydrates and 

 to qualitative examination for starch, dextrine 

 and gum. 



The paper reviews the collaboration work done 

 by the A. O. A. C. on condensed milk and evap- 

 orated milk during 1907 and 1908. 

 Effect of Fresh Manure on Denitrifieation and 



Plant Growth: E. B. Feed. 



This includes the results of field, pot and labo- 

 ratory experiments with fresh manure containing 

 large amounts of straw. The effect was studied in 

 experiments, where fresh manure was compared 

 with well-rotted manure, with and without the 

 addition of nitrate of soda. The loss due to de- 

 nitrifying bacteria present in the straw was meas- 

 ured by its effect on plant growth. 

 The Oolorimetric Determination of Nitrates in 



Soil Solutions containing Organic Matter: W. 



A. Syme. 



Potassium permanganate is added to the hot 

 soil solution, acidified with sulphuric acid, until 

 in excess. The solution is filtered, made alkaline 

 with sodium carbonate and evaporated to dryness 

 on water-bath. The residue is treateJ. with water, 

 filtered and diluted to its original volume. The 

 solution is now ready for the colorimetric deter- 

 mination of nitrates in the usual way with phenol 

 disulphonie acid and ammonia. 



There was no nitrate formation by the action 

 of the permanganate on the organic matter. 



Change in Composition of Unground Cereals dur- 

 ing Storage: Shebmaw Leavett and J. A. Le- 



CliEBO. 



Samples of corn, wheat, barley, oats and rye 

 in the unground state were allowed to stand for 

 two years. Every six months samples were drawn 

 for grinding and analysis. The authors found a 

 gradual change in all of the cereals taken. This 

 change becomes more rapid if the samples are 

 ground before aging. The most marked changes 

 are in the content of total sugar, 70 per cent, 

 alcohol soluble proteid, 5 per cent. KjSOi soluble 

 proteid and Stutzer water soluble proteid. Un- 

 ground corn lost 60 per cent, of its total sugar in 

 two years and its entire germinative power. There 

 was also evidence of a rearrangement of the pro- 

 teid molecules. 



In general corn, barley and oats in the order 

 given were found most subject to a change of 

 sugar content producing a loss. Wheat showed an 

 increase of sugar in two years. 



Corn, barley, rye, wheat and oats in the order 

 given show the greatest proteid change. 



The Importance of Experience in the Interpreta- 

 tion of the Results of Chemical Analyses: H. 

 H. Hanson. 



Incompletely described methods of analysis, un- 

 usual variations in materials under investigation, 

 skillful imitations of many important products, 

 and the personal equation of the operator make 

 necessary the most extreme care in interpreting 

 results of chemical analyses. The importance of 

 check determinations with known substances and 

 of repeated trials of unfamiliar methods is illus- 

 trated by reference to work upon paris greens, the 

 search for artificial color in various products and 

 examination of maple syrups and sugars and vari- 

 ous kinds of vinegars. Unusual variations in the 

 latter are cited and the importance of physical 

 tests emphasized. 

 Lead Test in Cider Vinegar Analysis: F. A. 



NOETON. 



