It is also a portent of the weather:
'Onion's skin very thin,
Mild winter's coming in;
Onion's skin thick and tough,
Coming winter cold and rough.'
It was the practice in some places to hang up or burn an onion as a safeguard against witchcraft, and the theory of this was that the devil respected it because it was an ancient object of worship. This seems a survival of the Egyptian story; but Mr. Hilderic Friend says that the Arabs, Chinese, and many other peoples, to this day employ onions, leeks, or garlic for preventing witchcraft, and that he himself has frequently seen them tied up with a branch of sago-palm over the doors of Eastern houses for this purpose.
The old custom of throwing an onion after a bride is doubtless well known. It had the same origin as the old Scotch custom of throwing a besom after a cow on its way to market, to avert the evil-eye, and insure luck.
The idea of bad dreams being associated with the onion seems due to the old herbalists. At all events, Coghan wrote in 1596: 'Being eaten raw, they engender all humourous and contemptible putrefactions in the stomacke, and cause fearful dreams, and, if they be much used, they snarre the memory and trouble the understanding.'
Old Gerarde had no opinion of the medical properties of the tribe. Of both leeks and garlic he wrote most disparagingly, as 'yielding to the body no nourishment at all,' but 'ingendereth naughty and sharpe bloud.'
Some of the other old herbalists treat it more kindly, and some ascribe almost every virtue to garlic and onion. Garlic came to be known as 'Poor Man's Treacle,' and in some old works is thus often described. But the word treacle here has no reference to molasses, and is probably derived from the Greek theriakos, meaning venomous, for garlic was regarded as an antidote against poison, and as a remedy for the plague.
Pliny long ago wrote of garlic as a remedy for many of the mental and physical ailments of the country people. It was used by the Romans to drive away snakes; and the Romans seem to have adopted this idea from the ancient Greeks. It was recommended by one old English writer as a capital thing with which to frighten away birds from fruit-trees; and has been recently recommended, in solution, as the best preservative of picture-frames from the defilement of flies. Bacon gravely tells of a man who lived for several days on the smell of onions and garlic alone; and there was an old belief that the garlic could extract all the power from a loadstone.
The belief that the eating of onions will acclimatize a traveller seems not uncommon in Eastern countries. Thus, in Burnes' Travels into Bokhara it is recorded that at Peshawur 'Moollah Nujieb suggested that we should eat onions in all the countries we visited, as it is a popular belief that a foreigner becomes acclimated from the use of that vegetable.'
And in Morier's Travels in Persia it is said: 'Those who seek for sulphur, which is found at the highest accessible point of the mountain of Damarvend, go through a course of training previous to the undertaking, and fortify themselves by eating much of garlic and onions.'