AQUEOUS HUMOUR, the clear watery fluid which fills the front part of the eyeball. It is enclosed by the cornea in front and the lens, suspensory ligament and ciliary body behind. The iris divides this small space into an anterior and a posterior cham ber. The fluid is secreted in the latter chamber by the ciliary gland and circulates through the pupil to be absorbed slowly in the anterior chamber into the circular canal of Schlemm. When this absorption is interfered with, the pressure of the accumu lating fluid increases, giving rise to the condition called glaucoma (q.v.). Injuries of the cornea may cause escape of the aqueous humour but if infection does not supervene the wound usually closes and the fluid reaccumulates.