Alt — Glandular Structures Appertaining to the Human Eye. 193 



muciparous character, as just such concretions are also found 

 in the ducts of the lacrymal glands (Fig. 39). 



GLANDS SITUATED IN THE TISSUE OF THE LIDMARGIN. 



In the dense tissue of the lidmargin, in front of the excre- 

 tory ducts of the Meibomian glands, the cilia or eyelashes are 

 implanted. These short curved hairs form three or four rather 

 irregular rows and emerge from the skin of the anterior part 

 of the lidmargin (Fig. 40). They are more numerous in 

 the upper eyelid than in the lower one, numbering in the 

 former from 100 to 150, in the latter from 50 to 70. 

 These numbers are, of course, only approximately correct. 

 The longest eyelashes lie in the middle line of the lids and 

 from here they grow smaller and smaller in the direction 

 towards the canthi. They are shortlived and drop out when 

 about from 50 to 100 days old. The curvature of the 

 eyelashes of the upper lid is concave upwards and convex 

 downwards, while that of the eyelashes of the lower lid is 

 just the reverse. 



Each eyelash is accompanied by sebaceous glands, usually 

 two, not infrequently three and four to one hair. These 

 glands do not differ in any particular from other sebaceous 

 glands of the hair of the skin and, therefore, it is not neces- 

 sary to give here a special description. 



There is, however, another kind of glands situated in the 

 intermarginal tissue of the eyelids, more especially, between 

 the roots of the eyelashes, which is of a somewhat peculiar 

 structure. These glands have been called modified sweat- 

 glands, although, as far as I can find, nothing is known con- 

 cerning the character of their secretion (Figs. 41, 42). 



In vertical (sagittal) sections through the whole thickness 

 of the eyelids one or two such glands are usually seen to lie 

 between the roots of two neighboring eyelashes or a little 

 nearer to the lidmargin, sometimes farther inwards between 

 the eyelashes and the tarsal tissue. In horizontal sections 

 (Fig. 43) and sections which are made parallel to the surface 

 of the eyelid, these glands are often found to be very numer- 

 ous. (I have never succeeded in getting such sections par- 

 allel to the surface which would go throuorh the whole width 



