The Association of Vitamins in Function

The Association of Vitamins in Function 1. Ascorbic Add, Vitamin P, and Capillary Resistance 

The preservation of normal powers of dark adaptation is another function in which, according to some workers, more than one vitamin is concerned. Kimble and Gordon (21) foimd that most individuals in their experiments who had poor dark adaptation and a low level of vitamin A in the blood could be brought into the normal ranges for both these criteria by dosing with vitamin A. Other individuals, however, failed to show the usual response. This led to the belief that other factors must be involved in the utilization of vitamin A for the synthesis of visual purple, and both riboflavin and ascorbic acid were tried as supplements to the action of vitamin A. Several othenvise normal subjects with poor dark adaptation and low blood vitamin A were given 200,000 I.U. of vitamin A daily as halibut liver oil, but failed to respond. It is perhaps rather difficult in the 

---