An ancient Indian text declares I will smell thee on the head, that is the greatest sign of tender love . In cultures where the sense of smell is highly valued, and odour is considered to be the essence of personal identity, interpersonal exchanges or mixing of odours is often carefully regulated. Many of these olfactory regulations serve important social functions, such as preventing sexual intercourse between close relatives. Among the Amazonian Desana, for example, all members of a tribal group a believed to share a similar odour. Marriage is only allowed between persons of different odours, so spouses must be chosen from other tribal groups.
Some rituals involve the exchange of differently scented ants.
Any prolonged mixing of similar personal odours is believed to cause disease in the people involved and in any children they may conceive. The dangers of odour-mixing are even more extreme for another Malay Peninsula people, the Temiar. The Temiar believe that each person has an odour-soul, located in the lower back. If you pass too closely behind a person, the odour-soul is disturbed and mingles with your body, causing disease. This must be prevented by calling out odour, odour whenever you approach a person from behind, so that the odour-soul is forewarned of the intrusion.