906 EXPERIMENT STATION RECORD. 



the afternoon milk which had been found by frequent tests to contain quite regularly 

 0.4 i)er cent more fat and practically the same percentage of solids-not-fat as the 

 morning milk. The percentages of milk sugar and ash were found to remain nearly 

 uniform throughout the .year, while the percentages of protein as well as of fatsliowed 

 a seasonal variation, being higher in the fall and winter than in the spring and 

 summer. A comparison of the results with analyses reported by Van Slyke and by 

 Richmond showed a close agreement, the fat and solids-not-fat having a tendency in 

 each case to rise and fall nearly together. The average composition of the milk for 

 the 2 years was as follows: Total solids 14.71, fat 5.26, solids-not-fat 9.25, protein 3.66, 

 milk sugar 4.84, and ash 0.75 per cent. 



During the same j^eriod analyses were also made of the milk of individual cows and 

 of certain groups of cows for the purpose of stutlying variations in other constituents 

 than fat. The average composition of 13 unusually rich samples was as follows: Total 

 solids 18.03, fat 7.76, solids-not-fat 10.27, protein 4.68, milk sugar 4.76, and ash 0.83 

 percent. The average composition of 6 samples low in solids-not-fat was as follows: 

 Total solids 11.53, fat 3.90, solids-not-fat 7.63, protein 3.34, milk sugar 3.59; and ash 

 0.71 per cent. "All of the results obtained accord with the conclusion recently 

 reached by Richmond that any deficiency of solids-not-fat is chiefly due to a defi- 

 ciency in the milk sugar, while any excess above 9 per cent is chiefly due to an 

 excess of protein." 



The following statements are made as regards the relation of protein to fat and to 

 ash: "The data at present available indicate that aside from the seasonal variation 

 already noticed, the percentages of fat and protein tend to rise and fall together, 

 though not to the same extent; that the average relation between the two is approxi- 

 mately expressed by the formula, protein =2+^ fat, but that the protein often 

 shows less variation from the average than this formula would imply. ... In 

 practically all of the samples examined the relation between protein and ash was 

 very nearly that found by Richmond and expressed by the formula, ash =0.36+0.11 

 protein. To agree more exactly with our averages, the formula may be modified to 

 read ash =0.38-f 0.1 protein." The milk sugar showed no tendency to vary with 

 any other constituent. 



Pasteurization of milk in bottles with, agitation, N. (terber an<l P. Wieske 

 {Rev. Gen. Lnit, 2 {1903), No. S,pp. 169-177) .—It is stated that a method of pasteur- 

 izing milk in bottles subjected to constant shaking has been in practical use by Ger- 

 ber for 15 years. The advantages of the method are set forth in this article and 

 recent literature relating to standards of pasteurization is reviewed. The method is 

 designated the Gerber method of pasteurization with agitation, and differs from other 

 methods in that during heating and cooling the apparatus containing the bottles of 

 milk is maintained in continuous oscillatory motion. The milk is therel)y heated uni- 

 formly and the formation of a surface membrane is prevented. By this process, which 

 is conside"ed more rapid and economical than pasteurization without agitation, the 

 milk is said to be left in a better condition as regards color, taste, and odor, and 

 there is less separation of the cream. Bottles containing as much as 5 liter may be 

 used. Until lower temperatures are justified by further investigations the authors 

 favor pasteurization at 65° C. for 30 minutes to 1 hour. 



Comparative tests of diflferent methods of distinguishing raw and heated 

 milk, ({. MuLLiE {Rev. Gen. Lait, 2 {1902), Nos. 4, pp- 77-S6; 5, pp. 100-lOS; /!, pp. 

 128-133; 2 {1903), Nos. 7, pp. 149-152; 8, pp. 178-182; 9, irp. 200-209).— f^umerons 

 methods which have been proposed for the detection of heated milk are classified 

 and described, and the results of tests In' the author are given in connection with the 

 discussion of each method. A bibliography is appended. Certain simple and easily 

 made tests based upon color reactions are considered as showing conclusively 

 whether milk has been heated to 78 to 80° C, at which temperature the danger 

 from pathogenic germs is practically eliminated. Ghemical methods liased upon 



