4 MILK AND DAIRY PRODUCTS PART 



The average amount of dry matter is given by Fleischmann 

 as 12'25 per cent., this figure applying to the mixed milk from 

 a large number of herds in Germany. The percentage of fat 

 in the dry matter is usually 27'75 per cent., the specific gravity 

 being 1'334 at 15 C. When the dry matter is freed from fat 

 it is on an average 8 '85 per cent, of the weight of the milk, and 

 the specific gravity lies about 1*6. 



Fat is present in milk in the form of an emulsion, that is, in 

 an immense number of minute globules which have a diameter 

 varying between 0'0016 and O'Ol mm. (see Fig. 1), In some 



FIG. 1. 1:400. Barthel photo. (Microphotograph of the Fat Globules in 



Milk.) 



cases, though, the fat globules vary as much as O'OOOl 0'022 

 mm., but the average diameter may be taken as approximately 

 0'003 mm. It is these microscopically small globules of fat 

 which along with the colloidial casein give to the milk its 

 peculiar white, opaque appearance. With regard to the 

 number of fat globules usually present in milk, the author 

 has calculated that the average quantity per cubic millimetre 

 of milk is 3,000,000 where a large number of animals are 

 concerned. These figures agree closely with those given by 

 Babcock, 1 Woll, 2 and Gutzeit. 3 The number and size of the 



1 Fourth Ann. Report N.Y. Agr. Expt. Sta., Geneva, 1886, p. 226. 



2 Agricultural Science, Vol. VI, No. 10, p. 444. 



3 Landw. Jahrbiicher, Vol. XXIV, 1895, p. 539. 



