Carmina Gadelica, Volume 2, by Alexander Carmicheal, [1900], at sacred-texts.com

THE 'mothan' (bog-violet?) is one of the most prized plants in the occult science of the people. It is used in promoting and conserving the happiness of the people, in securing love, in ensuring life, in bringing good, and in warding away evil.

When the 'mothan' is used as a love-philtre, the woman who gives it goes upon her left knee and plucks nine roots of the plant and knots them together, forming them into a 'cuach'--ring. The woman places the ring in the mouth of the girl for whom it is made, in name of the King of the sun, and of the moon, and of the stars, and in name of the Holy Three. When the girl meets her lover or a man whom she loves and whose love she desires to secure, she puts the ring in her mouth. And should the man kiss the girl while the 'mothan' is in her mouth he becomes henceforth her bondsman, bound to her everlastingly in cords infinitely finer than the gossamer net of the spider, and infinitely stronger than the adamant chain of the giant.

The 'mothan' is placed under parturient women to ensure delivery, and it is carried by wayfarers to safeguard them on their journeys. It is sewn by women in their bodice, and by men in their vest under the left arm.

An old woman in Benbecula said:--'Thug mi am mothan beannaichte do Ruaraidh ruadh mac Raoghail Leothasaich as a Cheann-a-deas agus e air a thuras do Loch-nam-madadh, dol ga fhiachain air bialabh an t-siorram agus fhuair e dheth ge do bha e co ciontach ’s a chionta ri mac peacaich'--'I gave the blessed "mothan" to red Roderick son of Ranald of Lewis p. 111 from the South-end (of Uist), and he on his journey to Lochmaddy to be tried before the sheriff, and he got off although he was as guilty of the guilt as the son of a sinner.' 'Ach a Chairistine carson a thug sibh am mothan dh’an duine agus fios agaibh gun robh e ciontach? Saoilidh mi fein nach robh e ceart dhuibh a dhol ga dheanamh'--'But, Christina, why did you give the "mothan" to the man when you knew that he was guilty? I think myself it was not right of you to go and do it!' 'O bhidh ’s aodaich! a ghraidhean mo chridhe agus a ghaoilean mo dhaoine, cha b’ urra dhomh fhein dhol ga dhiultadh. Bhoinich e orm, agus bhochain e orm, agus bhoidich a orm, agus chuir e rud am laimh, agus O! a Righ na gile ’s na greine, agus nan corracha ceuta, curra, de b’ urra dhomh fhein a gh’ radh no dheanamh agus an duine dona na dhubh-eigin na dheargtheinn agus na chruaidh-chas'--'O food and clothing! thou dear one of my heart, and thou loved one of my people, I could not myself go and refuse him. He beseeched to me, and he swelled to me, and he vowed to me, and he placed a thing in my hand, and oh! King of the moon, and of the sun, and of the beautiful, sublime stars, what could I myself say or do, and the bad man in his black trouble, in his red difficulty, and in his hard plight!' I remembered Bacon and was silent.

To drink the milk of an animal that ate the 'mothan' ensures immunity from harm. If a man makes a miraculous escape it is said of him, 'Dh’ of e bainne na bo ba a dh’ ith am mothan'--'He drank the milk of the guileless cow that ate the "mothan."'

I am not sure what the plant is--perhaps the bog-violet.