CONVENTION OF OFFICIAL AGRICULTURAL CHEMISTS. 411 



3 hours. The phloroglucin method for determining substances which 

 yield furfurol and the reporter's method for galactans were made pro- 

 visional. The reporter was instructed to test the necessity of a second 

 treatment with diastase in the diastase method for starch. A revision 

 and rearrangement of methods for feeding stuffs was ordered. 



The report of the committee on food legislation was read by H. W. 

 Wiley. This report recommended national pure-food legislation along 

 lines similar to those of the Paddock bill. The report of the commit- 

 tee was approved, and the committee was continued with instructions 

 to bring the matter to the attention of Congress. This committee is 

 H. W. Wiley, H. A. Huston, J. A. Myers, and A. S. Mitchell. 



DAIRY PRODUCTS. 



* 



The report of L. L. Van Slyke on dairy products was devoted prima- 

 rily to the results of comparative tests by 10 analysts of the provisional 1 

 and magnesium-sulphate methods for casein, and a modification of the 

 provisional method 1 for albumin in milk. The last two methods are as 

 follows : 



Magnesium-sulphate method. — To 5 gin. of milk are added 50 cc. saturated solution 

 of magnesium sulphate and this is heated to 40 to 45° C. to precipitate casein. The 

 precipitate is washed with warm solution of magnesium sulphate. In the nitrate the 

 albumin is precipitated by adding 0.3 cc. of 10 per cent acetic acid and boiling. 



Modified provisional method for albumin. — The filtrate from casein, precipitated 

 according to provisional method, is exactly neutralized by caustic alkali and then the 

 albumin is precipitated by adding 0.3 cc. of 10 per cent acetic acid and boiling. 



Both methods of determining casein gave fairly concordant results, 

 those obtained with the magnesium-sulphate method being somewhat 

 higher as a rule. The provisional and modified methods for albumin 

 gave very unsatisfactory results and appeared to be faulty. 



The provisional method for casein was made official. The magnesium- 

 sulphate method was made an optional official method. The modified 

 method for albumin was adopted as provisional until it can be further 

 studied. 



The Wollny method of saponification was made provisional and the 

 reporter was directed to test it in comparison with other methods of 

 saponification during the coming year. 



Formic aldehyde (1 part to 2,500 of milk) is substituted for mercuric 

 ehlorid as a preservative for milk samples. 



Water is to be determined in milk as follows : Heat to constant weight 

 from 1 to 2 gm. milk in a tared flat dish having a diameter of not less 

 than 5 cm., containing 15 to 20 gm. pure dry sand or without sand at 

 the temperature of boiling water. 



The second part of the report on dairy products was devoted to gen- 

 eral methods of testing quality and detecting adulterations in milk, 

 butter, and cheese (whole milk, filled, and skim milk), including cheese 



'U. S. Dept. Agr., Division of Chemistry Circ. 2. 

 10078— So. 5 2 



