DAIRY FARMING DAIRYING AGROTECHNY. 181 



Rusty cans and their effect upon milk for cheeseniaking, G. A, Olson 

 {Wisconsi)i Sta. Bui. 162, pp. 3-12, figs. 2). — The author has previously shown 

 (E. S. R., 20, p. SO), that various metals have considerable effect upon the action 

 of rennet. In the experiments reported in the present publication the effect of 

 iron rust on rennet action is shown. " Milk was placed in iron dishes and rusty 

 tin pans and was allowed to stand for definite periods of time. The required 

 time for the coagulation of 50 cc. of such milk with a standard solution of 1 cc. 

 of a 1 per cent commercial rennet extract at a temperature ranging from 87 

 to 88° F., was then observed. Milks kept in glass beakers were run as controls 

 under similar conditions. The time was noted at the moment the milk just 

 thickened." In these tests " it required from 1 to 16.5 minutes longer for the 

 same milk kept in the rusty pan to coagulate than in case of the milk kept in the 

 glass beaker." The acidity of the control milk was always higher than that.kept 

 in the rusty cans, but the difference was not great enough to account for the 

 differences in retardation. 



" Milk which had been allowed to stand in iron dishes for several hours had 

 a peculiar bluish grey color, indicating the presence of iron in solution. In sev- 

 eral instances the amount of iron dissolved in the milk was determined as iron 

 oxid. The maximum quantities of iron dissolved in the milk ranged from 1 to 

 I5 lbs. for every 1,000 lbs. of milk." The significance of this is shown by con- 

 sideration of the conditions of the cans in which milk is brought to the cheese 

 factory, and these conditions in America are contrasted with those prevalent in 

 certain sections of Europe. 



Varieties of cheese, C. F. Doane and H. W. Lawson ( U. 8. Dcpt. Agr., Bur. 

 Anim. Indus. Bui. 105, pp. 5-72). — This publication comprises a compilation of 

 descriptions and analyses of those varieties of domestic and foreign cheese about 

 which published information could be found by the authors. A list of publica- 

 tions giving the original sources of analytical data is included. 



Investigation of commercial rennet preparations, A. Burr and F. M. Ber- 

 BERiCH {^V he III. Ztg., 32 (1908), Xo. 25, pp. 313, 31-)). — The chemical composition 

 of a number of samples of liquid and powdered rennet preparations is reported 

 and the data are briefly discussed. 



The position of the oleomargarine industry in Sweden, A. Larson (K. 

 Lancltbr. Akad. Ilaitdl. och Tidslcr., 47 (1908), No. 1-2, pp. 21-29).— The 

 statistics of the industry during the last 20 years are given and discussed. 



The manufacture of oleomargarine in Sweden has gradually increased from 

 6,000 kg. in 1886 to 14,34.3,608 kg. in 1906. At the same time the imports decreased 

 from 813,621 kg. in 1885 to 6,296 kg. in 1900, the exports increased from 6,667 

 kg. to 658,642 kg., and the domestic consumption increased from 806,954 to 

 13,691,262 kg. The average price obtained for the year has ranged from 72 ore 

 (19.5 cts.) in 1897 to 113 ore (30.5 cts.) in 1902, the mean price for the period 

 given being 91.8 ore (34.8 cts.) per kilo. 



The manufacture of starch from sweet potatoes, C. C. McDonnell (South 

 Carolina St a. Bui. 136, pp. 7-50, pi. 1, figs. 11). — The investigations described 

 were undertaken to determine how much starch could be recovered commei'- 

 cially from sweet potatoes and to test the quality of the starch thus obtained 

 for different uses to which starch is put. The discussion includes nn account 

 of the method of culture, analyses of the sweet potato, the process of manufac- 

 turing starch therefrom and other data. The results are reported of investiga- 

 tions of two years on the manufacture of starch from sweet potatoes and of 

 tests of the starch for commercial purposes in laundry work and in the cotton 

 textile industries. 



In the author's opinion " it is practically settled that the starch produced 

 from sweet potatoes is of a high grade and suitable for use in many operations 



