THE EYE. 403 



stance, which permits it to play freely backwards and forwards. 

 The tendon from this point changes its direction by going back- 

 wards and outwards: it also becomes more flat, and is then in- 

 serted into the upper face of the sclerotica near its middle, just 

 beneath the internal margin of the rectus superior muscle. 



This muscle is the longest, but the most delicate of those be- 

 longing to the eyeball. According to Simmering, it draws the 

 eyeball forwards, and towards the internal canthus, and directs 

 the pupil towards the cheek. By the aid of the inferior oblique, 

 it draws the eyeball towards the nose: it expresses pride: it 

 appears to be greatly excited in anger.* 



The preceding muscles are all connected, either directly or 

 indirectly, with the theca of the optic nerve. 



6. The Obliquus Oculi Inferior is at the bottom of the orbit. 



It arises, by a small tendinous beginning, from the os maxil- 

 lare superius at the side of the os unguis, and, increasing in 

 size, it goes below the rectus inferior outwards and backwards, 

 and gets between the eyeball and the rectus externus. It is 

 then inserted into the outer face of the sclerotica, about half 

 way between the optic nerve and the cornea. 



It causes the eye to revolve on its axis, and turns the cornea 

 towards the nose. Its action, however, is much modified by 

 that of the other muscles. As one axis of the eye is a line 

 passing from the centre of the optic nerve, forwards and out- 

 wards, it will be found that each of the oblique muscles is in- 

 serted, at right angles, to this line; consequently, their simple 

 and unmodified action is to produce a revolution of the eye, on 

 its axis, in the line of their insertion, the first making the eye 

 roll inwards, and the latter outwards, on the two poles: they, 

 therefore, are strictly antagonists. 



Of the Lachrymal Apparatus. 



The apparatus for the tears (Organs Lachrymalid^ vise La~ 

 chrymaks) consists in the Lachrymal Gland, the Lachrymal 

 Ducts, the Lachrymal Sac, and a few other parts. 



* Bulbuni in priora et angulum intcrnum versus movct; pupillam deorsurn ad 

 genam dirigit; juvante musculo obliquuo inferiore bulbum nasum versus tralut; 

 auiiui fastum exprijnit; ira valde commoveri videtur. 



