The Gardnerian Book of Shadows, by Gerald Gardner, at sacred-texts.com
Power is latent in the body and may be drawn out and used in various ways by the skilled. But unless confined in a circle it will be swiftly dissipated. Hence the importance of a properly constructed circle. Power seems to exude from the body via the skin and possibly from the orifices of the body; hence you should be properly prepared. The slightest dirt spoils everything, which shows the importance of thorough cleanliness. The attitude of mind has great effect, so only work with a spirit of reverence. A little wine taken and repeated during the ceremony, if necessary, helps to produce power. Other strong drinks or drugs may be used, but it is necessary to be very moderate, for if you are confused, even slightly, you cannot control the power you evoke. The simplest way is by dancing and singing monotonous chants, slowly at first and gradually quickening the tempo until giddiness ensues. Then the calls may be used, or even wild and meaningless shrieking produces power. But this method inflames the mind and renders it difficult to control the power, though control may be gained through practice. The scourge is a far better way, for it stimulates and excites both body and soul, yet one e easily retains control. The Great Rite is far the best. It releases enormous power, but the conditions and circumstances make it difficult for the mind to maintain control at first. It is again a matter of practice and the natural strength of the operator's will and, in a lesser degree, of those of his assistants. If, as of old, there were many trained assistants present and all wills properly attuned, wonders occurred. Sorcerers chiefly used the blood sacrifice; and while we hold this to be evil, we cannot deny that this method is very efficient. Power flashes forth from newly shed blood, instead of exuding slowly as by our method. The victim's terror and anguish add keenness, and even quite a small animal can yield enormous power. The great difficulty is in the human mind controlling the power of the lower animal mind. But sorcerers claim they have methods for effecting this and that the difficulty disappears the higher her the animal used, and when the victim is human disappears entirely. (The practice is an abomination but it is so.) Priests know this well; and by their auto-da-fé, with the victims' pain and terror (the fires acting much the same as circles), obtained much power. Of old the Flagellants certainly evoked power, but through not being confined in a circle much was lost. The amount of power raised was so great and continuous that anyone with knowledge could direct and use it; and it is most probable that the classical and heathen sacrifices were used in the same way. There are whispers that when the human victim was a willing sacrifice, with his mind directed on the Great Work and with highly skilled assistants, wonders ensued but of this I would not speak.