PETROLEUM JELLY

Petrolatum is a flammable, semi-solid mixture of hydrocarbons, having a melting-point usually ranging from a little below to a few degrees above 100°F (37°C). It is colorless, or of a pale yellow color (when not highly distilled), translucent, and devoid of taste and smell when pure. It does not oxidize on exposure to the air, and is not readily acted on by chemical reagents. It is insoluble in water. It is soluble in chloroform, benzene, carbon disulfide and oil of turpentine.

There is a common misconception (resulting from the similar feel they produce when applied to human skin) that petroleum jelly and glycerol (glycerine) are physically similar. While petroleum jelly is a non-polar hydrocarbon hydrophobic (water-repelling) and insoluble in water, glycerol (not a hydrocarbon but an alcohol) is the opposite: it is so strongly hydrophilic (water-attracting) that by continuous absorption of moisture from the air, it produces the feeling of wetness on the skin, similar to the greasiness produced by petroleum jelly. The feeling is similar, but petroleum jelly repels water, and glycerine attracts it.

Chesebrough originally promoted Vaseline primarily as an ointment for scrapes, burns, and cuts, but physicians have shown that Vaseline has no medicinal effect or any effect on the blistering process, nor is it absorbed by the skin. Vaseline’s effectiveness in accelerating wound healing stems from its sealing effect on cuts and burns, which inhibits germs from getting into the wound and keeps the injured area supple by preventing the skin's moisture from evaporating.

Vaseline brand First Aid Petroleum Jelly, or carbolated petroleum jelly, containing phenol to give the jelly additional anti-bacterial effect, has been discontinued.