The histologic studies of 1Volbach and Howe(1) showed the antiscorbutic value of vitamin C in scurvy to be due to its effect upon the formation of intercellular cement substance, and it has been generally assumed that a similar action explains its effects in cases of increased capillary fragility corrected by vitamin C. However, the recent work of Hines and Parker ( 2 ) showed that large doses of vitamin C given intravenously could correct increased capillary fragility in some patients within a period of 10-30 minutes, indicates an additional action of the vitamin. The rapidity of this action suggests a direct chemical or enzymatic response and since the spreading factor, hyaluronidase, has been shown to increase capillary permeability( 3 ) , the present studies were carried out to investigate possible relationship of ascorbic acid to the hyaluronidase-hyaluronic acid system. Three methods were used for the study: Experiment 1. Experiments were first made to study the in vitro effect of vit. C on the hyaluronidase-hyaluronic acid reaction. For this purpose an impure solution of hyaluronic acid was obtained by filtering fresh vitreous humor from bovine eyes. One cc of this solution was mixed with an equal volume of serum and the amount of hyaluronidase* which would prevent precipitation of the hyaluronic acid by dilute acetic acid was determined(4), (the reaction was carried out at 37°C for 2 0 minutes with pH adjusted to 7.5). This amount of hyaluronidase was then mixed with the substrate which consisted of a serum mixture contaitning varying dilutions of buffered v l l , 601. *The hyaluronidase used in this study was obtained through the courtesy of Wyeth, Inc. 4. McClean, Biochem. J., 1943, v32, 169.vit. C. (Simultaneous controls were run using nmmal saline in place of vit. C). The effects on turbidity were $measured in a photolometer.A standard quantity of hyaluronidase colored with phyloxine dye, and brought to constant volume (0.5 cc) with iso-,tonic sodium chloride was injected into the skin of the 'shaved abdomen of a rabbit and Ithe amount of spread at the end of 2 0 minutes measured. The area of spread was calculated according to the formula for the area of anDxd 3 ameter of spread and d= smallest diameter of spread) ( 5 ) . Having determined the area of spread of the conltrol injections of hyalulronidase, the same quantity of enzyme was then injected with varying amounts of ascorbic acid while a constant volume of each injection was maintained by varying amounts of sodium chloride, The area of spread in 2 0 minutes was calculated by the above formula.In this set of experiments, the area of spread of the control solution of hyaluronidase was measured before, and at 10-minute interval's after, the intravenous injection of 500 mg of vit. C. Blood vit. C levels were also determined at varying intervals.Results. The in vitro tests showed that slight inhibition of the hyaluronidase action was produced by ascorbic acid. The greatest TABLE I. Effect of Mixturea of Aswrbic Acid and Hyaluronidase on Area of Sprea...