THE BYE. 



The eyelids are two movable folds 

 of the skin whose inner surface is 

 covered by a mucous membrane, 

 the conjunctiva. The skin on the 

 outer surface is thin, movable, and 

 presents fine hairs with small seba- 

 ceous glands, and also a few sweat 

 glands. At the lid margin papillae 

 are developed and the epidermis is 

 thickened. Along the outer bor- 

 der there are two or three rows of 

 large hairs, the eyelashes, the poste- 

 rior row of which possesses seba- 

 ceous glands and modified sweat 

 glands, called the glands of Moll. 

 The eyelids are further provided 

 each with twenty-five to thirty 

 large glands, known as Meibomian 

 or tarsal glands, whose ducts open 

 on the palpebral margin just in- 

 ternal to the eyelashes. Each 

 gland has a large central duct lined 

 by stratified epithelium and into 

 which numerous branched alveoli 

 open. The latter resemble the al- 

 veoli of sebaceous glands. The 

 Meibomian glands lie close to the in- 

 ternal surface of the eyelids and 

 their cells undergo a fatty change 

 and give out a fat-containing secre- 

 tion. 



In each lid there exists a frame- 

 28 



Fig. 298. Mei- 

 bomian or , tarsal 

 gland, reconstructed 

 after Bern's wax- 

 plate method (Hu- 

 her). 



