330 MANUAL OF HISTOLOGY. 



ened by placing in the ordinary per cent, solution of chloride 

 of gold. This last method shows very clearly 'the nerves of 

 the lid and conjunctiva, which take a deep violet or mauve 

 color. For rapid work the lids may be hardened in a saturated 

 solution of picric acid. They may then be stained with picro- 

 carmine or hsematoxylon, and mounted in glycerine or balsam. 

 (See chapter on General Methods.) 



The caruncula lachrymalis is a small, rounded mass of 

 skin ; it is placed between the lids at their inner angle, and 

 contains hairs, vessels, and glands, such as are found else- 

 where in the cutis. Its office is to prevent the overflow of tears. 



The conjunctiva. Just behind the tarsus, and separated 

 from it by a thin layer of fibrillated connective tissue, is the 

 conjunctiva, which, after lining the inner surface of the lid, 

 passes backward as a loose connecting fold (fornix) to the 

 sclera, over which it is reflected forward as far as the margin 

 of the cornea. The conjunctiva consists of an external or 

 epithelial layer and a tunica propria or proper investing mem- 

 brane. There is also a subconjunctival layer. 



The lower portion of the conjunctiva, where it takes its 

 origin from the margin of the lid, is quite smooth ; but near 

 the upper edge of the tarsus it becomes more or less infiltrated 

 with lymph- cells, and is thrown into numerous folds, which 

 have sometimes been mistaken for glands. The epithelial ele- 

 ments of this part vary much in shape ; in general there are 

 two layers : a superficial one, composed of cylindrical bodies 

 which are a continuation of the superficial strata of the skin, 

 and a deeper one of small, round cells, representing the changed 

 cylindrical elements of the Malpighian layer or rete mucosum. 



The tunica propria consists of fine connective- tissue fibres, 

 in which a few elastic fibrillse are interspersed. The subcon- 

 junctival layer resting immediately upon the tarsus is very 

 thin. That part of the conjunctiva forming the fornix has an 

 abundant subconjunctival tissue, which is composed of loose 

 elastic fibres and vessels ; the epithelial layers are also thicker 

 here, and small racemose glands, supposed to secrete mucus, 

 are also found there. 



On the conjunctiva covering the bulb the epithelium con- 

 tains here and there the large mucus-cells corresponding to 

 the goblet- cells of the intestines. It gradually begins to change 

 its character and passes over into the variety which is seen in 



