Serpent (symbolism) The serpent, or snake, is one of the oldest and most widespread mythological symbols. The word is derived from Latin serpens, a crawling animal or snake. Snakes have been associated with some of the oldest rituals known to humankind and represent dual expression of good and evil.
1 Osteoporosis, a condition characterized by reduced bone mineral density and increased bone fragility.  Rickets, a childhood disease characterized by impeded growth and deformity of the long bones. The earliest sign of subclinical vitamin D deficiency is craniotabes, abnormal softening or thinning of the skull.
Symptoms of vitamin A deficiency include: 1  Night blindness. 2  Thickening of the corneas. 3  Spots on the corneas. 4  Hazy corneas. 5  Blindness. 6  Scaly skin. 7  Thickening of the skin. 8  Respiratory tract infections. 9  Reduced immunity. 10  Growth retardation in the young. 11  Inability to fight infection in the young.