Drawing the inference from their experiment the authors have both pointed out the baneful influence of light on evolution of some vitamins and proved that the filter power of tinted packing is an important factor in this test mechanism: --vitamin C has a light development in an atmosphere without oxygen and is more sensitive about temperature than about light; --vitamin A is sensitive about both light and temperature. U.V. radiation applied to a product whose temperature is higher than 20 degrees C causes more damage to this product when packing is made of transparent glass; --the protector power of stained glass is still more obvious in vitamin B2.