CHAPTER IV 



PHYSICAL PROPERTIES OF MILK 



IF whole milk is examined under a microscope, the fat appears 

 in the form of globules with a pearly white luster floating in the 

 opaque serum (Fig. 2). If leucocytes are present, as they 



Cream 



Milk 



Skimmed-milk 



FIG. 2. The appearance of cream, milk, and skimmed-milk when examined 

 through a high-power microscope. The round bodies are fat globules that 

 float in the serum, or watery part of the milk. 



usually are, they appear as relatively large cells with one or 

 more nuclei. 



FORM OF THE FAT GLOBULES 



The fat exists in the milk not in solution but in the form of an 

 emulsion, the individual globules being held in their spherical 

 form by reason of the surface tension of the liquid fat. The 

 viscous nature of the milk-serum also aids in maintaining the 

 normal form of the globules. It was formerly believed that each 



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