42 INNEKVATION. [CHAP. xvn. 



cord, the tendo oculi, about a quarter of an inch long, which passes 

 horizontally to be fixed to the nasal process of the superior maxillary 

 bone. This latter is the principal attachment of the eyelids. The 

 eyelids enclose the orbicularis muscle between the skin and their 

 cartilages. Its fibres run in curves from .the lower border of the 

 tendo oculi and neighbouring part of the border of the orbit, encir- 

 cling the eye and forming a thin layer under the skin, both of the 

 lids, cheek, and brow, and returning to the upper border of the 

 tendo oculi. They are supplied by the portio dura, and perhaps by 

 some fibres of the fifth nerve, and act generally in answer to the 

 stimulus of air or foreign particles on the fifth nerve in the conjunc- 

 tiva, as well as of a too strong light upon the retina. The will exerts 

 a limited power over the orbicularis, but is quite unable to restrain 

 its action when sufficiently excited by the before-named stimuli. 

 The entire muscle consists of striped fibres. The lids are further 

 armed along their free margin by the delicate curved hairs, called 

 the lashes. These intercept the entry of foreign particles directed 

 against the eye, and assist in defending the organ from excess of 

 light. 



At the border of the eyelids, the skin becomes continuous with 

 their mucous lining, termed the conjunctiva. This membrane lies 

 upon the tarsal cartilages, and is then reflected over the front of the 

 globe, where it has been already in part described with the cornea. 

 Between the cartilages and the conjunctiva, and partially imbedded 



in the former, are the 

 Meibomian glands, which 

 may be seen through the 

 conjunctiva (figure 128). 

 Each gland consists of a 

 series of follicles, arranged 

 upon an elongated com- 

 mon duct, which empties 

 itself on the border of the 

 lid. They consist of a 

 basement membrane and 

 an epithelium (fig. 129) ; 

 the latter contains seba- 



View of the conjunctival surface of the Eyelids. The Mei- . i. , -M 



bomian glands are seen running towards the edges of the lids: CCOUS matter in ItS CCllS, 



I. The lacrymal gland removed with the lids. d. Orifices of j A. i 



its seven ducts on the conjunctiva. At the inner extremity of ancl 1S 1J 1 Continual COUrSC 



the borders of the lids, the orifices of the canaliculi (puncta ^L'f ,-. T, , -\ 



lacrymalia) are seen, o, o. Orbicularis muscle beyond the lids. OllOrmatlOn. ItSpartlClCS, 



when fully developed, are 

 thrust forward along the duct, and constitute the secretion. The 



