26 



EPITHELIUM 



fCH. III. 



occurs which consist of a substance called mucigen; these run 

 together, and are discharged from the cell as a brightly refracting 

 globule of mucin, leaving the cell with open mouth like a goblet, the 



FIG. 83. Glandular epithelium. Small lobule of a 

 mucous gland of the tongue, showing nucleated 

 glandular cells, x 200. (V. D. Harris.) 



FIG. 34. A small piece of the liver of 

 the horse. (Cadiat.) 



nucleus being surrounded by the remains of the protoplasm in its 

 narrow stem (see fig. 39). 



This transformation is a normal process continually going on 



FIG. 35. Section of human thyroid ; the few vesicles shown are lined by cubical epithelium, and con- 

 tain a colloid material. (After Schafer.) 



throughout life, the discharged mucin contributing to form mucus. 

 The cells themselves may recover their original shape after discharge, 

 and repeat the process later on. 



