THE BALL OF THE EYE. 431 



capsule, convey red blood : in which respect they correspond 

 with the hyaloidea ; for, if this were the case, vision would be 

 very much disordered by it. It may be that the moats or 

 specks seen in ophthalmia arise from the grosser particles of the 

 blood getting into these serous vessels, by the dilatation of, the 

 latter. 



The Lens and its Capsule are devoid of nerves, at least none 

 have been as yet traced into them. 



The Aqueous Humour (Humor Aquosus) occupies the space 

 which is between the anterior face of the crystalline capsule, 

 and the posterior face of the cornea. This space is unequally 

 divided by the iris into two chambers, of which the anterior is 

 in front of the latter membrane, and the posterior behind it. In 

 consequence of the convexity of the lens, the posterior cham- 

 ber has but very little depth just behind the pupil; but its space 

 is augmented at the circumference of the crystalline, so as to 

 leave room for the floating of the ciliary processes and for the 

 motions of the iris. The posterior chamber is, therefore, a cir- 

 cular vacuity; the centre of which, from the projection of the 

 centre of the crystalline, has scarcely any appreciable depth. 

 The anterior chamber, in its shape, resembles the segment of a 

 sphere: its depth depends essentially on the size and the pro- 

 jection of the cornea. 



The aqueous humour is perfectly transparent, and almost as 

 fluid as water. The analysis of Berzelius exhibits 98 parts of 

 water, 1 of hydrochlorate and lactate of lime, 75 of some ani- 

 mal matter soluble in water, and a very small quantity of albu- 

 men. From the latter circumstance it will be understood how 

 this fluid refuses to coagulate on the addition of alcohol or of 

 mineral acids to it, and is only rendered in a very slight de- 

 gree turbid by them. The rapidity of the exhalation of this 

 fluid is remarkable; when the whole of it is lost in the opera- 

 tion for cataract, it is regenerated in from twenty-four to thirty- 

 six hours. Its source has been sought for in suppostiitious canals 

 and glands, but the more probable opinion is, that it may come 

 from any or all of the exhalent arteries of the chambers of the 

 eye 



Like the other two humours of the Eye, the aqueous is fur- 

 nished with a capsule, but whether it is complete or not is yet 



