190 Trans. Acad. Sci. of St. Louis. 



somewhat nasally rem ved from the palpebral lacrymal 

 gland. 



When studying horizontal sections through the eyelids such 

 little glands are sometimes found, also, to lie close to the 

 temporal and nasal edges of the tarsus of the upper as well 

 as the lower lid, and partly in the ocular conjunctiva. They 

 are formed of one or two minute glandular lobules. All of 

 these glands are of exactly the same histological structure as 

 those generally recognized as lacrymal glands. Their ex- 

 cretory ducts, from their situation, are rather short. They, 

 also, are lined with cylindrical epithelium. Their external 

 orifice lies usually in the palpebral, sometimes in the ocular 

 conjunctiva (Figs. 23 to 25). 



There is no reason, as far as I can see, why these small 

 isolated acinous glands should not also be looked upon as 

 lacrymal glands, as they differ in no way histologically from 

 them. The difference in size is the only one I can recognize. 



The presence of these glands alone, then, could explain 

 why, after the operative removal or the destruction of the 

 orbital and the larger palpebral lacrymal glands in the tem- 

 poral half of the eyelids, the surfaces of the eyeball and eye- 

 lids do not become dry. It is, furthermore, clear that when 

 a chronic inflammation, involvingthe whole of the conjunctiva, 

 gradually leads to its shrinkage and to the consequent oblitera- 

 tion of the excretory ducts and secondarily to atrophy of all 

 these glands (and of some to be described presently), as for 

 instance trachoma, xerophthalmus must result. 



GLANDS SITUATED IN THE TARSAL TISSUE OF THE EYELIDS. 



The tarsal tissue proper of the eyelids contains two forms 

 of glands, namely, the so-called Meibomian glands and the 

 acino-tubular (Waldeyer) glands. 



The Meibomian glands are found in the upper lid to be 

 about 30 in number, while in the lower lid they are only 

 about 20. There are, however, individual variations as 

 to these numbers. They are long, slender glandular struc- 

 tures, somewhat resembling the pancreatic glands, consisting 

 each one of a central duct to which are attached numerous 

 round, vesicle-like acini (Fig. 26). These central ducts 



