The use of body fluids, such as blood, saliva or semen, is a powerful element in many magical traditions. They can be used as a medium by which to send the magical intention, or to propitiate gods or other wights whose assistance is needed for the working, or to forge a sympathetic bond with the target of the magic.
Blood
Where visible staining was required, blood is the only medium that was used. The blood that was used was usually the sorcerer’s own, and in some cases it was to be drawn from a specific place on the body, the sites mentioned being the left arm, the left hand, the right side of the chest, the middle of the chest, the thigh, under the big toe, and under the tongue.
These specific blood-letting sites are mentioned in only eight spells of widely varying intentions.
The left side of the body – often considered nearer the heart and therefore more powerful – is cited in only four of the eight examples; if people then were, as now, predominantly right-handed, it would only be logical to hold the knife in the right hand and cut the left arm or hand.
Sometimes (in four spells) the blood of an animal was used, and in three of the four cases it was that of a calf. The reasoning here may have been that the animal was both innocent and valuable, although it should not necessarily be assumed that the beast was killed in the process of obtaining its blood.
All three spells are intended to create a talisman – one for success in gaming, another to preserve luck, and the third for protection against evil – and in all three the stave is to be carved on special parchment or paper.
One spell in the Stockholm MS, to obtain a woman’s love, employs snake’s blood, and the stave is carved on the floor in the victim’s path.
Spit or Saliva
The sorcerer’s own saliva was also fairly frequently used, usually in conjunction with a finger .This was often the chosen fluid when the ‘carved’ surface was the sorcerer’s own skin, or when the magical intention was to be transmitted secretly and by direct contact
Breast Milk
Milk is used for three of the spells, but never to ‘stain’ a stave or any other carved sign.
Poo
The Icelandic word used is saur, and I will use the solid, evocative, English word ‘shit’ in my own translation:
“If you want a man to sleep. Take a dead man’s shit or a [living] man’s shit, or man’s shit and ödu (now unknown Icelandic word) earth, and lay in the middle of his chest, and carve these staves on a piece of baleen with steel.”