676 THE EYE 



glands open into the hair follicles and occasional sudoriparous glands 

 pour their secretion upon the epidermal surface. 



At the margin of the lid its cutaneous portion is reflected inward, 

 and at its inner angle becomes directly continuous with the palpebral 

 conjunctiva. The free margin of the lid presents, therefore, an outer 

 angle, an inner angle, and an intermediate surface. 



Two or three rows of large stiff hairs, the eyelashes or cilia, project 

 from the outer angle, and large sebaceous glands open into their follicles. 

 Other smaller sebaceous glands open directly upon the free surface. 

 These sebaceous glands are sometimes called the glands of Zeiss. 



The intermediate surface of the margin of the lid retains the char- 

 acter of the skin, though no hairs are found in this portion. Peculiar 

 sweat glands, the glands of Moll, occur in the derma of this part. 



At the inner angle of the lid the epidermis abruptly changes its char- 

 acter to that of the conjunctiva, the derma of the cutaneous surface 

 being continuous with the submucous connective tissue of this membrane. 

 At the inner angle also, are the openings of the peculiar large sebaceous 

 glands, the tarsal glands (of Meibom), their orifices forming a con- 

 tinuous punctate row of pores barely visible to the naked eye. 



The tarsal (Meibomian) glands are long compound saccular 

 glands,, about thirty in the upper, and about twenty in the lower lid, 

 whose secreting saccules open into a common, axially placed duct which 

 extends the whole length of the gland. Each saccule is filled with cells 

 in various stages of fatty degeneration and is exactly similar in structure 

 to the saccules of the ordinary sebaceous glands. The glands are em- 

 bedded in the connective tissue of the conjunctiva and are so large as 

 to form projecting ridges on its surface, which are disposed in vertical 

 lines radiating from the row of glandular orifices at the margin of the 

 lid. At their blind extremities the glands are often slightly bent or 

 curved upon themselves, and this portion is embedded in a dense mass 

 of fibrous tissue known as the tarsus. 



The tarsus in each eyelid forms a very dense plate-like mass of areolar 

 connective tissue which is so dense and resistant as to erroneously 

 suggest a cartilaginous structure. It is inserted between the conjunctiva 

 and the orbicularis muscle. It is thickest toward the free margin of 

 the lid, but becomes progressively thinner in the opposite direction, until, 

 as a mere fibrous membrane, the palpebral fascia, it is continued to the 

 margin of the orbit. 



The conjunctival portion of the lids, the palpebral conjunctiva, 

 consists of a peculiar stratified epithelium and a thin connective tissue 



