THE EYE. 759 



The palpebral conjunctiva is a reddish membrane, 0-12-0-16 of a line 

 thick, very intimately connected with the posterior surface of the tarsi, 

 and consisting of a dense layer of connective tissue corresponding to 

 the cutis, 0-08-0-11 of a line thick, and of a squamose epithelium, 0-04 

 of a line in thickness, containing deeper cells of an elongated form, and 

 more superficially, polygonal, slightly flattened, nucleated, and (so far 

 as I have seen in Man) non-ciliated cells. Papillae also, similar to those 

 of the cutis, are met with in the palpebral conjunctiva, some of which 

 are smaller and more cylindrical, whilst others, particularly towards the 

 point of reflection of the membrane where it is generally thicker, are 

 larger (as much as 1-10 of a line long), more verrucose and fungiform. 

 At the line of reflection itself, Krause describes minute racemose mu- 

 cous glands, 1-5-1-26 of a line in size, but which do not always exist. 

 The conjunctiva scleroticce, is white, less dense and thinner than that of 

 the lids, tolerably rich in fine elastic fibres, and loosely and movably 

 attached to the sclerotic by an abundant submucous connective tissue, 

 containing more or fewer fat-cells. Papillce are wholly wanting in this 

 portion, except at the line of reflection, as well as glands, whilst the epi- 

 thelium is well developed, as on the conjunctiva cornece, and beneath it 

 there is not unfrequently an outermost layer of the proper mucous mem- 

 brane, in the form of a very distinct structureless, narrow seam. At 

 the margin of the cornea, particularly in elderly persons, the conjunc- 

 tiva scleroticce forms a slight annular elevation J-l line broad, the an- 

 nulus conjunctivce, which encroaches a little upon the cornea at the lower, 

 and especially at the upper border. The corneal conjunctiva has been 

 already described, and it only remains to notice the plica semilunaris, 

 or the third palpebra at the inner canthus of the eye. This is a simple 

 duplicature of the sclerotic conjunctiva, which rises in front into a coni- 

 cal elevation the caruncula lachrymalis, in which are seated about a 

 dozen fine hairs, surrounded by an equal number of rosette-like sebace- 

 ous follicles 1-5-1-4 of a line in size, encompassed by numerous fat-cells. 

 The lachrymal apparatus consists, in the first place, of the lachrymal 

 glands a certain number of larger and smaller compound racemose 

 glands, disposed in two groups termed the superior and inferior lachry- 

 mal glands, and in the structure of the larger and smaller lobules, as 

 well as in the rounded gland-vesicles, 0-02-0-04 of a line in diameter, 

 precisely resembling the salivary and mucous glands ( 134, 135). The 

 excretory ducts of these glands, 6-12 in number, perforate the conjunc- 

 tiva in the fold between the outer part of the eyelid and the globe of 

 the eye ; they are excessively fine canaliculi, composed of connective 

 tissue, with a few nuclei and elastic fibrils, and of a cylindrical epithe- 

 lium. It is extremely difficult to display these canals in man, whilst in 

 animals (the Ox for instance) they are easy of demonstration. The pas- 

 sages by which the tears are conveyed away from the eye are con- 



