784 EXPERIMENT STATION RECORD. 



Comparative investigations of the applicability of different 

 tests for ascertaining the fat content of milk, F. Friis (Ber. K. 

 Yet. Landbohojslcoler Lab., Copenhagen, 1898, pp. 112). — The tests com- 

 pared in this report are Gerber's acid butyrometer, Fjord's control cen- 

 trifuge (cream test), and the "lactoscope." Earlier experiments at this 

 station have demonstrated the accuracy of the Gerber test. The lacto- 

 scope is an apparatus invented by a Danish engineer, P. V. P. Berg, 

 for determining the quality of milk. It is a Fjord centrifugal cream 

 test, modified so as to be used with an Alpha separator. The appara- 

 tus consists of a hollow steel cylinder fitting into the Alpha separator 

 stand. Loose aluminum plates shaped to hold 24 test tubes are placed 

 in this cylinder, which will hold 16 plates, or 384 test tubes at a time. 

 The milk in the tubes is heated to 40° C. and rotated for 35 minutes at 

 a speed of 0,000 revolutions per minute. The results agree with those 

 obtained with the Fjord cream test, each "per cent cream " being equiv- 

 alent to about 1.5 per cent fat. The author concludes that the lacto- 

 scope when operated according to directions may be used with perfect 

 assurance of accuracy in separator creameries and private dairies. — 

 f. w. WOLL. 



Rancid butter, A. J. Swaving (Ztschr. Untersuch. Nahr. u. Genussmtl., 

 1808, No. 11, pp. 759-702). — The author reports two series of experiments 

 with butter of unquestionable purity. In the first series, samples of 

 melted and unmelted butter were kept in open and closed vessels, both 

 in the dark and in the light, for 15 months, the volatile fatty acids being 

 determined at the beginning and end of the experiment. There was a 

 loss in volatile fatty acids in keeping the unmelted butter in both open 

 and closed vessels, but a small increase in case of the melted butter. 



The second series of experiments was like the first, except that the 

 samples were kept for 5 years. The unmelted samples molded and 

 assumed a dark color, while the melted samples remained a yellowish 

 white and showed very little change in appearance. There was an 

 increase in volatile fatty acids of the melted butter ranging from 1.7 to 

 2.3, the increase being greatest in the closed vessels. There was a loss 

 of from 2.9 to 11.8 in case of the unmelted butter, the loss being mate- 

 rially greater in the open vessels, and in the dark. 



The indications from these experiments are that in keeping unmelted 

 butter there is a loss of volatile fatty acids, while in the case of melted 

 butter the Keichert-Meissl number increases slightly. It is suggested 

 that the difference in the behavior of melted and unmelted butter may 

 be due to the presence of casein, milk sugar, and water in the unmelted 

 butter. The greater loss of volatile fatty acids in darkness than in 

 light is taken as a suggestion of the action of bacteria. 



Experiments with a self-regulating pasteurizing apparatus, V. 

 Henriques and V. Stribolt (Ber. K. Vet. Landbohojslcoler Lab., Copen- 

 hagen, 1896, pp. 25; Tidsslr. Norshe Landbr., 5 ( 1898), No. 10,pp. 527-533).— 

 The authors have adopted the principle of tlie Roux thermoregulator 

 in constructing an apparatus which regulates the supply of milk to a 



