CHAPTER III. 



MICROSCOPY OF MILK IN GENERAL. 



If milk is examined through a microscope one chiefly sees 

 numerous small fat cells floating in the fluid or milk plasma. These 

 will be considered later, but at first the cells and cell fragments 

 originating from healthy and affected udders will be discussed. 

 Between the milk globules, by which term the small fat droplets 

 are designated, bodies may be seen which are hard to define unless 

 stained. After special treatment, however, they may be readily 

 recognized as cells or their fragments, or as a precipitation of 

 soluble or suspended substances. 



Since the external skin of the udder, and the lining of the milk 

 passages and milk secretory ducts in the udder are of similar for- 

 mation, we naturally are only concerned with the upper layers of 

 pavement epithelium, cylindrical epithelium, and the deeper cubical 

 epithelium of the terminal ducts and alveoli, and only in severe 

 tissue changes would cells of other parenchymatous parts appear 

 in the milk. Naturally in such an actively working organ, even in 

 a physiological normal condition, leucocytes of the most varied 

 kind, and even red blood corpuscles may be found. In cases of 

 special stimulation from physiological or pathological causes, the 

 resulting cell mixture may be of a most varied character depending 

 upon the location of the stimulation, and its quality and duration; 

 hence at times certain leucocytes, and again red blood cells or 

 epithelia, may predominate in the mixture. 



1. Cells from compound pavement epithelium. Following 

 the intensive manipulation and stimulation of the teats by milking, 

 the appearance of cells from the upper layers of the pavement 

 epithelium of the outer skin, and the milk ducts is natural. As 

 a matter of fact in the fresh milking periods during which irrita- 

 tion from the extraction of the milk is especially evident, the 

 milk always contains fine folded platelets of round, oval, or irreg- 

 ularly distended and curved borders, which frequently when folded 

 in several layers, appear as small clasped cysts without special 

 structure. 



These bodies have been described by Winkler, and were con- 

 sidered by him as indications of pathological changes. The author 



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