14 WILLIAM II. F. ADDISON AND HAROLD W. HOW 



a mature condition, containing hair shafts and having outlets 

 through the surface epithelium (fig. 12, h). 



At this ten-day stage some variation in the condition of the 

 junction epithelium was noted in animals from different Utters. 

 The description as given above was taken from the most advanced 

 specimen and from a region of the lid about midway between 

 the inner and outer canthi. In other specimens which were not 

 quite so far advanced, the junction epithelium as measured from 

 the inner to outer groove was greater in extent, and no kerato- 

 hyalin granules were seen in the epithelial cells of the conjunc- 

 tival furrow. 



Eleven-day rat 



Along the midline of the junction epithelium some of the cells, 

 which contained the keratohyalin granules in the preceding 

 stage, have now advanced to the stage of complete cornification. 

 The connecting epithehal cells constitute a narrow eosin-staining 

 band, bounded on each side by flattened cells, containing numer- 

 ous keratohyalin granules. The granules are large and few in 

 number within each of the cells of the one or two rows nearest 

 the cornified zone and are smaller and more numerous in the 

 cells of the succeeding two or three rows. 



Twelve-day rat 



The narrow keratinized band in the junction epithelium is 

 becoming more distinct (fig. 13). This is the result of more of 

 the cells containing keratohyalin granules becoming cornified. 

 The dimension measured from conjunctival to epidermal side is 

 lessened, and at the midpoint of the lid is about 75ij.. Laterally 

 to the middle region of the Ud, this measurement is consider- 

 ably greater. As the process of disjunction approaches an end, 

 a shght but appreciable difference is seen in the appearance 

 and dimensions of the keratinized band of epithelium in different 

 parts of the same hd. At the middle of the eyelids the process 

 of disjunction is more advanced, as compared with the con- 

 dition laterally. This is to be correlated with the observation 



