Let us see how that would work if anyone whose eyes are a little opened looks at the aura of a person—the lowest part of that aura, if you will, in etheric or astral matter: let us say, astral. You will notice a large number of colours continually flashing through it and changing; and if you examine those colours, every one, as you know from your ordinary study, representing a certain definite vibration in matter—every colour is nothing more than a certain vibration in matter, a vibration with a definite wave-length—if you watch those changing colours in the aura you will find that they are either generated by a state of consciousness or give rise to it. Suppose, for instance, you find a person in a mood of devotion, engaged perhaps in prayer—you can see them by the score in any Christian church. Watch the astral aura of that person, and you will find that the whole of it is vibrating in a way that gives you the colour of blue, blue everywhere predominating, the whole of the aura suffused with that colour. But you will also find, if there is in that congregation a quiet person who was not feeling devotional when he came into that congregation, that gradually his astral body will be affected by the vibrations in the astral bodies near him, and that those vibrations imposed upon him from without will produce a devotional mood within him. You can start it, then, at either end: either the mood producing the appearance, the vibration, or the vibration producing the mood. Take it in another form: have you never felt when you yourself were perfectly good-tempered and some very irritable person came up to you, have you never felt that you yourself were becoming irritable?—not that you had anything to be irritable about, but merely because the other man was, and it needs considerable control, control over the astral body, to prevent the irritation of the person who comes near you from affecting your own previously placid mood. If you have not observed this, keep watch over yourself during the coming week, and you will find how continually you reproduce the emotions of the people with whom you come into contact. What is the mechanism of it? Very simple. That person’s astral body is vibrating in consonance with the emotion he is feeling. Those vibrations of his astral body set up vibrations in your astral body, a perfectly mechanical thing. But because it is your astral body, the matter you have appropriated, those vibrations in it produce in you the corresponding mood of irritation. Hence the common ethical precept given by every great teacher, to return good for evil. That is by a deliberate effort of the consciousness to throw yourself into the mood which is opposite to the evil mood of the person with whom you come into contact. If you do that, then your own mood will overbear in your astral body the vibrations imposed upon it from without, and your astral body will begin to vibrate in correspondence with your own good emotion instead of with