It was equally sacred when the stone was a mere cenotaph erected in memory of a departed chief or saint. Such are found in all lands and in all cults. They are the _menhirs_ of the Celts, and the grave-stones of the Koders of India, often painted in strong colours.[183] Certain stones, especially those we call “precious,” the gems, have physical traits of transparency, lustre, and colour, which have ever made them prized, and led to the belief that they exercise peculiar powers on the mind. Throughout Asia and America the varieties of jade or nephrite, a greenish, semi-translucent mineral, has had a wide-spread reputation for sacred meaning and magical potency. The _chalchiuhite_ of the Mexicans, small green stones, believed to control the weather and representative of the goddess of the waters and the rains, were of this material. By attentively gazing into the transparency of a quartz crystal, the Maya shaman of Yucatan still believes that he will see in its depths, unfolded by the god whose dwelling it is, the picture of the future and the decrees of fate. _4. Trees and Plants._—Primitive man was arboreal. A hollow tree was his home, its branches his place of refuge, its fruit his sustenance. Naturally the tree became associated with his earliest religious thoughts. It represented his protecting deity. He would not willingly injure it. When the Mandans cut a pole for their tents, they swath it in bandages so that its pain may be allayed. The Hidatsas would not cut down a large cottonwood tree, because it guarded their tribe. The Algonquins decked an old oak with offerings suspended to its branches, for the same reason.[184] Trees from their dripping foliage, and because their shade was associated with the grey of a cloudy day, were believed to make the rains and thus to refresh the fields and fertilise the seeds of the vegetable world. The step was easily taken to extend this to all germs, animal as well as vegetable. Thus the tree came to symbolise the source of Life, and to represent both the clouds and rains and the fatherhood of men and brutes. It could cause flocks to multiply and the barren womb to conceive.[185] Among the Mexicans, the tree was invoked as Tota, “Our Father,” and was spoken of as god of the waters and the green foliage. Some particular species was chosen as the totem of various American gentes, and in the earliest legends of Greece and Persia sundry famous families traced their descent from a tree. These ideas led to the mythical association of the tree with the origin of life, and with various objective expressions of this in the cult.