Chap. IV. The Anatomy of a HORSE. 41 



fi-om thence running along the Bottom of the Bram ; after 

 increafing and growing broader, they arc divided into a 

 great many Twigs, which receive outer Coats from the 

 Dura Mater, having only before a fingle Integument from 

 tlie Pia Mdter. Many of thefe Twigs pafs through the 

 Holes of the Sieve-like Bone to theNofe, where they help 

 to compofe the Organs of Smelling. 



The fecond Pair are the Optic, or feeing ^hfecondPair, 

 Nerves; thefe rife a httle behind the former^ 

 out of the Medulla Oblongata: At their Rife they are 

 fomewhat foft, being cover'd only with the Pia Mater ; 

 but as foon as they reach the Dura Mater, they become 

 cloathed by it, as the Olfa^ory Nerves above defcribed. 

 This outermoft Coat conllitutes the Sclerotica, or horny 

 Tegument of the Eye ; and from the Pia Mater proceeds 

 the next Coat of the Eye call'd the Uvea, from its Re- 

 femblance to a Grape in Colour : And laftly, the mar- 

 jowy Subftance forms the Retina, or Net-like, w^hich by 

 fome is call'd its third Coat, 



The third Pair are call'd the Eye- "The third Pair, 

 movers : Thefe arife from the Bottom of 

 the l^edulla Oblongata : At the Rife they are united, which 

 is the Reafon why fome believe, when one Eye is carried 

 towards any Objed:, the other is alfo direded towards the 

 lame. As the Optic Nerves pafs thro' the firfl Hole of 

 the Wedge-like Bone, thefe pafs through the fecond, until 

 they come to the Mufcles of the Eye, where they are dif- 

 perfed ; by their aduating the Mufcles, the feveral Motions 

 of the Eye are performed. 



The fourth, or Pathctick Pair : Thefe The fourth Pair. 

 take their Rife different from all the reft, 

 viz. from the Top of the 'Medulla Oblongata, behind the 

 Kates and Te/ies, and pafiing along the Side of iht Medulla, 

 are afterwards hid in the Dura Mater, until they reach the 

 Hole thro' which the laft Pair do pafs, which they accom- 

 pany, until they are inferted in the Tr^^Z'/^jr Mufcles of the 

 Eyes ; thefe are called by Dr. Willis the Pathethick Nerves^, 

 which move the Eyes in all PalTions and AfFedlions. 



The fifth Pair take their Beginning in a ^^^^ r^^^ p^^y 

 Horfe a litile below the former, tho' in a hu- ^ 

 man Subje^ft they feem to arife from the Cerebellum. Thefe 

 are made up of a Bundle of Fibres gather'd together, fo 

 . that they look to be a Number of Nerves fpringing from 

 pne common Origin, which fend out Branches into all Paris 



of 



