91 



determiued as recommeuded last year, but the metliod of computing the 

 weight of the contents of a flask at any temperature, according to the 

 formula given on page 17 of Laudolt and Biirnstein's tables,* is made an 

 alternate. Water. — 1.5 to 2.5 grams of tl>e butter are to be dried to con- 

 stant weight at the temperature of boiling water in a fiat-bottomed dish 

 presenting a surface of at least 3 square inches. The use of clean, dry 

 sand or asbestos is considered advisable. Total fat. — The dried butter 

 from the water determination is dissolved in the dish with absolute 

 ether or with " 70° benzine." The contents of the dish are then trans- 

 ferred, with the aid of a wash bottle filled with the solvent, to a weighed 

 Gooch filter, and washed until free from fat. The crucible and contents 

 are heated at tlie temperature of boiling water to constant weight and 

 the weight of fat calculated. Alternate method for fat. — Water may be 

 determiued by drying the butter on asbestos or in sand and the fat ex- 

 tracted with anhydrous alcohol-free ether, in an extraction apparatus. 

 The extract, after evaporation of the ether, is heated to constant weight 

 at the temperature of boiling water. 



The Kjeldahl method was adopted as an alternate method for the de- 

 termination of curd, the nitrogen factor G.25 to be used. 



Milk: Water. — In the description of the method for the determination 

 of water, as recommended for last year, the word platinum is to be 

 stricken out, thus allowing the use of dishes of glass or porcelain as well 

 as platinum. The use of sand in drying is made optional. Nitrogen. — In 

 determining total nitrogen according to Kjeldahl, the previous evapora- 

 tion of the milk may be omitted. Fat. — The Adams method was again 

 accepted, but the following modifications recommended. Instead of ex- 

 tracting each coil of paper before use, a constant correction, based upon 

 determination of the extract from a large number of like strips, may 

 be supplied. The milk or cream is to be run on to the paper from a 

 pipette, to avoid the danger of selective absorption. The methods of 

 Morse, Piggott, and Burton, and that of Macfarlane, as alternates, are 

 discarded. Siujar. — The reduction of alkaline copper solution is made 

 an alternate method. Ash. — The method remains unchanged, except 

 that the use of the muffle in burning is made optional. 



The reporter for the ensuing year was requested to test and report 

 on the various rapid methods for milk analysis. 



An extensive report on sugar was presented by Prof. H. W. Wiley; 

 accompanying this a full index to the literature of carbohydrates since 

 the publication of Professor Tollens' book, with important abstracts, 

 was submitted. 



The report of the committee on Avays and means for securing more 

 thorough methods for the analysis of foods and feeding staffs, was pre- 

 sented by Prof. W. O. Atwater. This report urged the pressing ne- 

 cessity of such abstract studies as will bring definite knowledge of the 

 proximate ingredients contaimd in each substance to be analyzed, 



' Physikaliscb-CbemiscUe Tabellea von Laudolt und Bornstein. Berlin, 1883. 



