EXUDATION. 



[ 250 ] 



EYE. 



cells; mature epithelial cells, of the pave- 

 ment, cylinder, or ciUated forms ; exudation 

 globules, or granule - cells ; pus and pyoid 

 corpuscles ; coloured corpuscles of the blood; 

 pseudo-membranous flakes of fibrine ; tuber- 

 cule ; fatty matter in the form of globules, 

 rarely of crystals; earthy matters, amorphous 

 or crystalline; various substances derived 

 from the food, as muscular fibre, starch- 

 granules, cellular tissue, &c. ; entozoa, or 

 fragments of them, as portions of the cysts 

 or hooks of Echinococcus ; infusoria and 

 algse, as Monads, Bacteria, Sarcina, &c.; 

 carbon and true pigment, either in the free 



Fig. 213. 



Section of the membranes of the eye, near the ciliary processes. 



S^/., sclerotica ; C, cornea ; Pr, cil., ciliary process ; Ca, anterior chamber ; 

 Cp, posterior chamber; Cv, vitreous humour; C.P,, canal of Petit; L, lens ; 

 /, iris; «, conjunctiva of the cornea, — epithelial layer; b, subjacent elastic layer; 

 c, fibrous layer of the cornea ; d, membrane of the aqueous humour ; e, its epi- 

 thelium ; /, end of the memljrane and its fusion with the fibres g, which pass to 

 the iris at i, forming the pectinate ligament ; h, venous canal ; A", ciliary liga- 

 ment or muscle arising from the inner wall I of the venous canal ; m, pigment- 

 layer of ciliary processes ; n, that of iris ; o, fibrous layer of iris ; p, its epithe- 

 lium ; q, anterior wall of capsule of lens ; s, epithelium of capsule ; /, anterior 

 thickened portion of hyaloid membrane; ti, zonule of Zinn, or anterior lamina 

 of hyaloid membrane; v, posterior lamina of the same ; w, colourless epithelium 

 of the ciliary processes ; «>', anterior end of this epithelium ; x, conjunctiva of 

 sclerotica ; z, posterior wall of the capsule of the lens. 



Magnified ]2 diameters. 



state or contained within epithelial cells ; 

 and fragments of pulmonary tissue. 



The aid of the microscope in the examina- 

 tion of the expectoration v\dll occasionally 

 throw an unexpected light ujDon the dia- 

 gnosis of disease. 



EXUDATION, and EXUDATION COR- 

 PUSCLES. See Inflammation. 



EXUVIUM (exuvia; or exuviae, plur.). — 

 The cast or shed skin of animals. The exu- 

 vium of many minute animals exhibits the 

 form and structure of the skin, and the parts 

 upon which it is moulded, better than these 

 can be discerned in the living animals, on 

 account of its transparence. 

 The exuvium of the Tri- 

 ton (PI. 40. fig. 11) exhi- 

 bits the cellular structure 

 of the epidermis very beau- 

 tifully. 



EYE. — From want of 

 space, we are compelled to 

 assume that the reader pos- 

 sesses a knowledge of the 

 component parts of the eye 

 and their relative position, 

 as far as can be obtained 

 w ithout the use of magni- 

 fying glasses. These parts 

 are described in all works 

 upon anatomy, and in most 

 of those upon optics. 



The outer fibrovis coat of 

 the eye is commonlyregarded 

 as consisting of tw o parts : 

 one anterior, smaller and 

 transparent, — the cornea ; 

 the other, posterior, larger 

 and opaque, — the sclero- 

 tica. The history of the 

 development and the mi- 

 nute structure of these, 

 proves that they must be 

 considered as forming a sin- 

 gle continuous membrane. 

 The sclerotica (fig. 213. 

 Scl.), or tunica albuginea, 

 covers the posterior four- 

 fifths of the ball of the 

 eye ; it is a milk-white, 

 very firm, fibrous mem- 

 brane, continuous poste- 

 riorly with the sheath of 

 the optic nerve, becoming 

 gradually thinner in front, 

 except at its termination, 

 where the tendons of the 

 recti muscles become fused 



