i MILK 57 



constant, or nearly so, whilst in milk or cream they diminish in 

 proportion to the increase of fat, the following formula, based 

 upon the relation between fat and total solids (both expressed 

 in percentages of the cream), can be used : 



d=f+- ~~^ X constant, 

 100 



in which d = dry matter or total solids and /= fat contents. 



The size of the constant (per cent, total solids not fat) lies 

 within narrow limits, and for cows of the Low Countries' breeds 

 is 8'7. The amount of total solids not fat in the rnilk of 

 various breeds of cows is shown in the following table, which 



is due to J. Konig : 1 



Per cent, total solids 

 not fat. 



Swedish 8 -48 



East Friesland 8'67 



Dutch 8-71 



Holstein 8'76 



Algauer 8'92 



Shorthorn 9 '35 



Ayrshire 9'48 



For cattle in the North of Germany the constant may be 

 taken as 8 '7 5 ; in other countries and for other breeds the 

 constant would be different, as the above table shows. 



By determining the total solids of the cream and placing 

 this in the above formula, the fat contents is obtained. As 

 previously mentioned, the change in the constant, due to the 

 breed and country, would necessitate a determination of it for 

 the particular district in which the test was being used. 



The manipulation is very simple. Into a small flat basin, 

 which contains about 20 c.c. of very finely powdered pumice 

 stone, 6 g. of the cream are weighed in the usual way from a 

 beaker. After drying for 2 J hours in the water-oven at 100 C., 

 the dry matter is weighed. The percentage of fat can then be 

 calculated with the help of the above formula, or more simply 

 and conveniently by reference to the table drawn up by Weibull 

 (Table IV in the Appendix), where the fat contents is shown 

 directly from the weight of the total solids. This table is based 

 upon a constant of 8'7. Where sour cream has to be tested, the 

 method with ammonia, described on p. 21, can be used in order 

 to get the cream into a fluid state, after which the desiccation, 

 &c., can be carried out in the manner described above. 



1 Die menschlichen Nahrungs- und Genussmittel, Berlin, 1899, Vol. II, 230. 



