88 



LACRYMAL ORGANS. 



junctival layer on the cornea than the microsco- 

 pical structure of this membrane, for there is 

 the greatest resemblance between the structure 

 of the sclerotic conjunctiva and the investment 

 of the cornea."* Eble thus retracts the opinion 

 he formerly expressed against the existence of a 

 conjuuctival layer of the cornea. 



Externally the sclerotica overlaps or en- 

 croaches on, more or less, the edge of the 

 cornea. In certain constitutions, and especially 

 in old persons,f I have observed that the 

 overlapping part of the sclerotica is thicker and 

 more opaque than usual perhaps also en- 

 croaching more extensively on the cornea. The 

 conjunctiva covering the overlapping sclerotica, 

 especially when the latter is to any considerable 

 extent, appears in its independent form with its 

 chorion fully developed, and although it ad- 

 heres to the subjacent overlapping part of the 

 sclerotica very closely by cellular tissue, it by 

 no means presents the same intimate union 

 with the subjacent structure and the same rudi- 

 mentary state which the conjunctival extension 

 over the transparent cornea has. In an eye 

 before me in which the overlapping sclerotica 

 is to some considerable extent at the upper 

 edge of the cornea, I easily raised up in a fold 

 and then separated by dissection the perfectly 

 developed conjunctiva from over the part. The 

 conjunctiva covering the overlapping part of the 

 sclerotica has a vascular connexion with the 

 latter no otherwise than by the anastomoses of 

 the proper vessels of each a vascular con- 

 nexion, which indeed subsists between the scle- 

 rotica and conjunctiva elsewhere. The dispo- 

 sition just described is connected with a point 

 in the pathology of the eye, viz. the bluish 

 white ring which is observed to encircle the 

 cornea more or less completely in certain inter- 

 nal inflammations of the eye, and so frequently 

 in what is called arthritic iritis that it has been 

 considered a diagnostic of it, but certainly with- 

 out just grounds. 



Before explaining the cause of the appear- 

 ance, I would request it to be remembered that 

 the insertion of the ciliary ligament is at some 

 little distance from the apparent margin of the 

 cornea; that the vessels which form the red zone 

 of the sclerotica in the internal inflammations 

 of the eye, and in inflammation of the proper 

 substance of the cornea, are vessels which send 

 branches inwards to the iris, opposite the ciliary 

 ligament, branches outwards to anastomose 

 with those of the conjunctiva, and lastly, 

 branches which, following the original direc- 

 tion, go to be distributed to the proper sub- 

 stance of the cornea. These vessels are not 

 apparent in the healthy state, and one set of 

 them only may become apparent in inflamma- 

 tion. Thus in inflammation of the iris, they 

 will be apparent only as far as opposite the in- 

 sertion of the ciliary ligament. Between this 

 and the clear part of the cornea is the opaque 

 overlapping part of the sclerotica, which of 



* Medicinische Jahrbiicher des k. k. oester- 

 reichischen Staates ; Neueste Folge. Band xvi. 



t The arcus senilis, it is to be remembered, is not 

 here the question. 



course not being in the way of the progress of 

 the vessels towards the inflamed part, remains 

 white as usual, and the cornea not being 

 affected the minute branches to its proper sub- 

 stance remain unenlarged and unseen. Hence 

 the overlapping part of the sclerotica is seen in 

 contrast between the abruptly terminating red 

 sclerotic zone on the one hand, and the trans- 

 parent cornea (appearing dark on account of the 

 dark structure behind it) on the other, forming 

 the bluish white ring. 



From this explanation the bluish white ring 

 round the cornea ought to exist more or less in 

 all internal inflammations of the eye, unless 

 obscured by vascularity of the conjunctiva in 

 inflammation of the cornea. So it does ; but 

 in persons of otherwise sound constitution and 

 not of advanced age, the overlapping sclerotica 

 is so transparent and sometimes also to so small 

 an extent, that it is not strongly contrasted by 

 the transparent cornea. It is otherwise the case, 

 however, in certain persons, especially such as 

 are advanced in life, in whom the encroach- 

 ment of the sclerotica and fully developed con- 

 junctiva on the cornea exists to a great degree 

 and in a very opaque state, that the bluish 

 white ring appears in the exaggerated distinct- 

 ness which has commonly attracted the notice 

 of surgeons. 



The condition of the eye necessary for the 

 distinct appearance of the bluish-white ring 

 round the cornea occurring principally in old 

 persons of bad constitution, and these being 

 the very persons in whom an internal inflamma- 

 tion of the eye very often presents what is 

 called the arthritic character, are circumstances 

 which readily explain the error of supposing 

 the bluish white ring round the cornea diagnos- 

 tical of arthritic iritis.* 



III. Lacrymal organs properly so called. 



Under this head are comprehended : 1. The 

 secreting lacrymal organs, or the lacrymal gland 

 and its excretory ducts. 2. The derivative la- 

 crymal organs, or the passages by which the 

 secretions of the lacrymal gland and of the 

 conjunctival surface are drawn off into the 

 nose, viz. the lacrymal points, the lacrymal 

 canalicules, the lacrymal sac, and nasal duct. 



The lacrymal gland and its ducts may be 

 considered as a branched diverticulum of the 

 conjunctiva; the derivative lacrymal organs, to 

 use the expression of M. De Brain vi lie, as 

 nothing but the continuation of the conjunctiva 

 and its anastomoses with the olfactive mem- 

 brane. 



1 . Secreting lacrymal organs. 



Lacrymal gland, Glandula lucrymalis; Fr. 

 La glande lac rymale ; Ital. La glundula lagri- 

 male; Germ. Die Thrancndruse. 



When the lacrymal caruncle was supposed 

 to filtrate the succus lacrymalis, and the lacry- 

 mal points to excrete it, the lacrymal gland 

 was called glandula innominutu. 



The lacrymal gland (fig. 13) consists 

 of two masses, an upper and a lower. The 

 upper mass, or glandula lacrymalis supe- 

 rior, lies in the lacrymal fossa, a depres- 



* London Medical Gazette, vol. xxiii. p. 817. 



