STRUCTURE OF THE EYELIDS. 44.") 



The plexiform tissue which traverses the fasciculi of these 

 two portions, and in the interstices of which each transversely 

 striated muscular fibre is imbedded, is in the new-born child 

 composed of a very delicate plexus of branched nucleated cells. 



The Meibomian glands number from thirty to forty in the 

 upper and from twenty to thirty in the lower lid. They are 

 imbedded in a dense tissue situated between the middle and 

 posterior layers, which by manipulation can be separated from 

 the other tissues, and which has received the name of the car- 

 tilage of the eyelid or tarsus. In sections it appears that the 

 so-called tarsus is continuous with the connective-tissue sub- 

 stratum of the middle and posterior layers, and is differen- 

 tiated only by the peculiar arrangement and appearance of its 

 tissue from that which is around it. 



The tissue of the tarsus is composed of more or less regu- 

 larly arranged fasciculi of connective tissue, the fibres of which 

 are broader, more lustrous, and resistant to the action of re- 

 agents than those of fibrillar connective tissue. In the imme- 

 diate vicinity of the glands the fasciculi run horizontally from 

 before backwards, forming larger or smaller arches around the 

 several acini. Here and there the several fibres run obliquely, 

 and decussate with each other. Near the muscular layer on 

 the one hand, and the connective tissue on the other, the fasci- 

 culi pursue an opposite direction. They here run parallel to 

 the surface of the lids, and throughout their whole extent from 

 above downwards. Between the fibres, or attached to certain 

 fibres, are distributed, though not always in large numbers, 

 elongated nuclei, with pointed extremities. No cartilage cells 

 have hitherto been found in them. The transition of the 

 tarsal connective tissue into the connective tissue of the 

 adjoining layer occurs gradually, whilst ordinary fibrillar con- 

 nective tissue takes the place of the stiff fibres of the tarsus. 



The Meibomian glands are arranged in linear series parallel 

 to the surface, and their excretory ducts open on the free 

 border of the lid, near its posterior margin; their blind ex- 

 tremities do not quite extend to the line of junction of the con- 

 junctiva palpebrte and fornix conjunctiva. Each Meibomian 

 gland is composed of a relatively wide excretory duct, from all 

 sides of which short bulbous acini are given off. The excretory 



