This shows that there is a mystery that lies behind movement. There are certain vibrations which take a particular direction under certain conditions, and the visible signs of all vibrations can be seen in man's movements or the expression of his countenance. It does not take one moment for the expression to change from pleasure to pain, from calm to horror, from love to hate. That shows that all the atoms of man's body, the veins, tubes and muscles, and the lines formed by their movements, are under the control of the heart, and every change that takes place in the heart shows on man's face, so that one who knows the language can read it. People who see each other often can read such changes from the expression, because each grows accustomed to know and recognize the changes of facial expression in the others, but it is the development of intuition which gives the clearness of vision by which one can see more completely.