The present study was undertaken in connection with the clinical test of chlorin as a therapeutic agent in disease of the upper respiratory tract, reported by Dr. M. F. Jones and Dr. Charles Garofalo.
The general plan of the work permitted the patients to breath air containing chlorin while seated in a specially prepared room. The chlorin was liberated into the air from a pressure tank through an instrument which measured the quantity delivered by displacement of water.1 In addition, the air in the room was subjected to analysis to determine the actual concentration of chlorin present at frequent intervals during the treatment. In general, the sensations experienced by the patients do give some criterion as to the concentration of the chlorin, but a more precise analytic control is regarded as desirable. Even those who are working every day with this treatment are unable to tell accurately the concentration of