i 4 MILK AND DAIRY PRODUCTS PART 



cells, there are fragments of dung and fodder, hair from animals 

 and human beings, vegetable fibres, grains of sand, parts of 

 insects in short, everything that can be found in the dust of 

 the stall. The amount of separator slime can vary from 

 0'03-0'25 per cent, of the weight of the milk, but generally it 

 does not exceed O'l per cent. 



FIG. 2. 1 : 350. Barthel photo. Microphotograph of separator slime. 1 



The above curtailed description of the properties and com- 

 position of cow's milk applies only to milk under normal 

 conditions, for immediately after calving there are considerable 

 differences both in its nature and the compounds which it 

 contains. Directly after the birth of the calf the milk, which 



Water 67 '50 per cent. 



Casein 12'56 



Cell substance 13'28 ,, 



Nitrogen-free organic matter ... 3 '99 ,, 



Ash 2-67 



100-00 per cent. 



is then known as colostrum or " beestings," has a yellow or 

 yellowish-brown colour, and the specific gravity varies between 

 1*040 and 1*080. Colostrum differs markedly from ordinary 

 milk; it is thicker and it also coagulates on boiling; the 

 so-called " calf-cheese " is obtained in this way. 



1 Mycelial threads, particles of dung and leucocytes, 

 sarcely visible with this enlargement, 



, , ~ . The bacteria are 



scarce 



