DAIRY FARMING DAIRYING. 285 



between the following groups of impurities found in the samples, as 

 follows: (1) Litter: Sawdust, peat dust, straw, and chaff particles; (2) 

 fodder particles; neither of these components bear any evidence of hav- 

 ing passed through the alimentary canal; (3) dung particles: Spores 

 of a Pilobolus sp., fodder particles filled with mycelium and filamentous 

 bacteria, epithelium cells, cow hairs, etc.; (4) particles of straining cloth 

 or towels; and (5) particles originating from man, dyed and undyed 

 woolen hairs, dyed cotton fibers, etc. 



All samples examined contained mainly the particles belonging to 

 group 1, but groups 2 and 4 were always represented; group 3 was 

 only conspicuous in a marked degree in 2 cases; and group 5 was 

 present in 40 to 50 per cent of the samples. — p. w. woll. 



A simple method for determining fat in separator cream, M. 

 Weibull (A', landt. Akad. Handl. Tidskr., 35 (1896), pp. 370-379).— The 

 author determines the solids in the cream by drying on powdered 

 pumice stone (not to exceed gr. per 20 cc. pumice stone) for 2i hours 

 at 100° C, and calculates the fat content from the following formula: 



/=1.1 t — 9.5 



where /= fat content, and t = total solids of the cream. The formula 

 is based on the fact that the solids-not-fat of cream is comparatively 

 uniform, viz : 



* 100-/ 

 *=/+T00~ xa ' 



The value of the constant a varies with the different breeds of cows, 

 and is assumed to be 8.7 in the formula for /'given above. A table is 

 constructed on the basis of this formula showing the fat contents of 

 cream corresponding to total solids ranging from 17.7 to 42.1 per cent. 

 If the cream to be tested is from breeds having a higher percentage of 

 solids-not-fat than 8.7, the author recommends subtracting a certain 

 fraction from the values given in the table, e. g., 0.8 per cent for cream 

 from cows of the Ayrshire or Shorthorn breeds, whose milk contains 

 9.4 per cent solids-not-fat (Konig). 



The author compared the results obtained by the use of the preced- 

 ing formula with gravimetric analysis in case of 19 samples of separa- 

 tor cream, and 8 samples of hand-skimmed cream, and also gives 21 

 cream analyses made by others where both total solids and fat in the 

 cream were determined. The maximum difference obtained by the 

 author with separator cream was 0.6 per cent, and the average 0.32 

 per cent, while hand-skimmed cream gave an average difference of 0.6 

 per cent. Six of the latter samples were from sour cream. The aver- 

 age difference for separator cream (23 analyses) was 0.27 per cent. 

 The results show that the calculated fat content may differ more than 

 2 per cent from the gravimetric analysis in case of hand-skimmed 

 cream which has soured before being sampled, and the method is 

 therefore not recommended for such cream. — f. w. woll. 



