576 THE CONJUNCTIVA. [SECT. 229. 



tinuation of the external skin, lines the posterior surfaces of the 

 eye-lids, and is then reflected upon the eye-ball, and covers the 

 most anterior part of the sclerotic and the whole of the cornea. 

 The conjunctiva palpebrarum is a reddish membrane, o , i2 / " to 

 - i6'" thick, which is very intimately connected with the posterior 

 surface of the tarsus, and consists of a dense layer of connective 

 tissue corresponding to the cutis, and measuring o - o8'" to o* 1 1'" in 

 thickness; on this is placed a lamellated epithelium, 0-04'" thick, 

 with elongated cells in the deeper portions, and on the surface, 

 polygonal, slightly flattened, nucleated cells, which have no cilia, as 

 far as I have been able to observe, on the human conjunctiva. 

 Papillae also, similar to those of the cutis, exist on the conjunctiva 

 of the eye-lids, some of them small and more cylindrical, others 

 being larger, up to -^~" in length, and of a wart-like or fungiform 

 shape; these larger papillae are found especially in the neighbour- 

 hood of the reflexion of the membrane, where the whole structure 

 becomes increased in thickness. At the flexure itself, C. Krause, 

 Sappey, and W. Krause describe small racemose mucous glands, 

 T V to i'" in diameter, which W. Krause has counted to the 

 number of forty-two in the upper lid, between two and six only in 

 the lower. The conjunctiva sclerotica? is white, less dense and 

 thick than that of the lids, well supplied with fine elastic fibres, 

 and is loosely attached to the sclerotic by a large quantity of sub- 

 mucous connective tissue, containing more or less fat-cells. Papillae 

 and glands are completely absent from this membrane, when it is 

 traced past the flexure ; but, on the other hand, the epithelium is 

 well developed; while on the conjunctiva corneal, beneath 'the epi- 

 thelium, we may frequently observe a very distinct, structureless, 

 narrow band, forming the outermost lamina of the proper mucous 

 membrane. At the edge of the cornea, the sclerotic conjunctiva, 

 especially in old people, forms a slight circular swelling, \ to 1 line 

 broad, the annulus conjunctiva, which extends for a little way over 

 the cornea, at its upper margin particularly. We have already 

 spoken of the conjunctiva of the cornea, and have only now to 

 make mention of the plica semilunaris, or third eye-lid, at the 

 inner angle of the eye. This is a simple fold of the sclerotic con- 

 junctiva, the anterior portion forming a rounded elevation, the 

 caruncula lacrymalis, which contains about a dozen fine hairs, 

 with an equal number of racemose sebaceous glands, £'" to |'", 

 lying around them, and surrounded by numerous fat-cells. 



The lacrimal apparatus consists essentially of the lacrymal 

 (/lands — a number of compound racemose glands of various sizes 







