134 MILK AND ITS HYGIENIC RELATIONS 



consider that they are the ordinary type of polymorphonuclear 

 leucocytes which are found universally in the blood stream. These 

 cells, as is well known, are the scavengers of the blood and destroy 

 bacteria which gain access to the organism. Hewlett considers 

 that they cannot be leucocytes because he has not obtained any 

 evidence of amoeboid movement on examining these cells, and 

 he has not noted any phagocytosis as shown by the presence of 

 bacteria in the cells. Other observers report the presence of 

 bacteria in the bodies of these cells, which leads them to the belief 

 that the cells are derived from the blood stream and are the ordinary 

 polymorphic variety of leucocytes. If these cells are the scavenging 

 cells of the body, their number should rise in any pathological 

 condition of the udder. 



The work upon the relative numbers of the different varieties 

 of cells found in milk when there is a high cell count, and possibly 

 some inflammatory condition, is rather fragmentary and not 

 very conclusive. At the present time it does not seem possible to 

 decide the origin of the cells, but it is not unlikely that the kind 

 of cell may differ in the milk of different species. 



CHAPTER VII 



ON THE CELLULAR CONTENT OF MILK 



THE presence of cells in normal milk has long been known. Interest 

 arises out of this fact mainly on two grounds. There is evidently 

 a physiological side which is concerned with the origin of these 

 cells and their function, and another one relating to public 

 health. It has been suggested that the number of cells present 

 might give an indication of the condition of the gland, i.e. 

 whether healthy or not. This implies the necessity for 

 using a method whereby the number of cells can be accurately 

 estimated. 



The two questions are difficult to separate completely. It 

 is not proposed here to deal at any length with the nature of the 

 cells found in milk, since to do so would involve a consideration of 

 the physiology and histology of the gland, which must be regarded 

 as somewhat outside the scope of the present work. Neither 

 the origin nor the function of these cells has as yet been definitely 

 determined. It is possible that precise information may never 

 be arrived at, since it is not at all unlikely that the origin will 

 differ somewhat in different conditions 



The Nature of the Cellular Elements present in Milk. 

 The discussion which has arisen round the cellular elements of 

 milk has been mainly concerned in endeavouring to decide 



