ANIMAL MECHANISM. 109 



HUMORS OF THE EYE. 



By humors, medical writers mean the fluids which dis- 

 tend the eye-ball. They are three in number, pos- 

 sessing different densities, and varying much in quality, 

 quantity and use. Beside fulfilling the first intention, 

 viz., distension, they are so purely transparent, as to offer 

 no obstruction to the free passage of light. Too much 

 care cannot be bestowed on the anatomy of these fluids 

 by surgeons, as they are the seats of many remarkable 

 diseases. Those only interested in this description, as 

 general philosophers, by close examination, will have a 

 perfect idea of them, and will consequently understand 

 the real nature of some of the many" causes that weaken 

 the power of vision, or ultimately produce a total blind- 

 ness. The gratification afforded by the examination of a 

 bullock's eye, tracing the several parts by this paper, 

 will be an ample compensation for the labor, because it 

 will forever fix on the mind interesting discoveries, and 

 lead the reader, insensibly, to a course of reflections, 

 productive of much intellectual enjoyment. 



AQUEOUS HUMOR.* 



The aqueous humor is the first in the order of demon- 

 stration, lying directly back of the cornea, so clear, 

 that one unacquainted with the existence of it, would not 

 suspect a fluid there. In volume, it is far less than the 

 others : it keeps the cornea prominent, always at the 

 same distance from the iris, in the early periods of life. 

 The space occupied by the aqueous humor, is called the 

 anterior chamber of the eye. (See fig. 2, letter/.) Pass- 

 ing freely through the pupil, it also fills an exceedingly 

 thin apartment, the circumference of the iris, called the 

 posterior chamber. Thus it will be comprehended, that 

 the iris, or in familiar language, first curtain, is actually 

 suspended and floating in a liquor. Were it not for such 

 a contrivance, the iris would soon become dry and shriv- 

 elled, by the intensity of the sun, and therefore rendered 

 totally unfit to perform its appropriate office of opening 



* Aqueous like water. 

 VOL. I. NO. V. 10 



