A Chemical Study of the Normal Aqueous Humor. ∗

Abstract

The preliminary study of the composition of the normal aqueous humor in the dog was undertaken to serve as a basis for further investigation of the changes which occur as a result of chemical and physical alterations in the eye. The determination of total nitrogen, 1 non-protein nitrogen, 2 protein nitrogen, amino-acid nitrogen, 3 urea nitrogen, 3 uric acid, 4 creatinine, 2 glucose, 5 and refractive index was made. Because of the small quantity of eye fluid, the ordinary methods for the estimation of these substances were modified by the employment of smaller quantities of reagents, and by the use of a microcolorimeter. The refractive index was obtained by the means of a Pulfrich-Zeiss dipping refractometer. The fluid was removed by paracentesis of the anterior chamber, with a fine bore needle, under ether, amytal or cocaine anesthesia as indicated in the table. About 0.6 to 0.8 cc. of aqueous humor was obtained each time. It was found that 0.2 cc. was sufficient for any one of the analyses except that for amino-acid nitrogen, for which 0.5 cc. was required.

The following table shows the refractive index and the average results in milligrams per 100 cc. of eye fluid. This is a preliminary report.