THE EYE. 357 



network of the lig. pectinatum and surrounding its elements, 

 upon the border of the iris, where a perfect epithelium is again 

 met with. 1 



The cornea in the adult is nearly altogether non-vascular, 

 whilst, as J. Muller and Henle first observed ('De membr. 

 pupill.,' p. 44), in the human embryo and foetal Lamb a rich 

 capillary plexus exists in the conjunctiva cornea, but which 

 does not appear to extend as far as the centre. Towards the 

 end of foetal life and after birth, this plexus diminishes in 

 breadth, in animals to a less extent than in Man, so that in 

 the latter we find blood-vessels at the margin of the cornea, 

 only in a zone of £"' or at most of 1"' in width. These 

 vessels are for the most part the fine and finest capillaries of 

 0*002 — 0-004"', forming one or several rows of arches, and 

 thus terminating ; they are lodged in the substance of the 

 conjunctiva, which here extends, in the form of a distinct layer, 

 for a short distance upon the cornea, ceasing in its anterior 

 structureless lamella. In animals these superficial or conjunc- 

 tival vessels also exist, but are usually much better displayed, 

 and extend further towards the centre ; frequently over half 

 the radius, or even beyond it. Besides these, deeper capil- 

 laries derived from the sclerotic also occur in the substance of 

 the cornea, usually accompanying the nervous trunks, in which 

 they either form a single or a few very much elongated loops, 

 or extend a little beyond them; they all terminate in loops, 

 the finest vessels constituting which, like the superficial capil- 

 laries, measure scarcely more than 0*002'". I have also noticed, 

 in Man, these peculiar corneal vessels accompanying the 

 nervous trunks, although not constantly and never so much 

 developed. 



Nothing certain is known of the lymphatics of the cornea 

 (vid. also, Arnold, 'Anat/ II, p. 988), though I have recently 



1 [This statement is directly opposed to Mr. Bowman's observations (op. c., p. 22), 

 who says, " that it would appear from what has been said concerning the conversion 

 of the posterior elastic lamina at its border into fibrous tissue, which in part passes 

 through the aqueous humor to the iris, that this epithelium must cease with the 

 elastic lamina, since there is no longer any stratum upon which it can rest." He 

 has been unable " to discover the smallest appearance of it upon the pillars of the 

 iris, and conceives therefore that it is limited to the cornea." And according to 

 the same accurate observer, the front of the iris has no true epithelial investment, 

 — Eds.] 



