Why, for instance, should old women always carry a sprig of Southernwood to the kirk in their Bibles? The leaves are, however, said to be disagreeable to insects. The Lavender stalks usually placed in linen both keep away insects and have a pleasant old-world scent. A great many of the properties possessed by plants are of the most extraordinary and unsuspected nature. The roots of the Madder (_Rubia tinctorum_), for instance, when they are eaten by swine or other animals, change the colour of their bones, which become pink. This curious property has actually been made useful, for physiologists have employed madder in the study of the growth and development of bone. In India and other eastern countries one is often shocked and surprised to find an apparently quite healthy native expectorating blood in a most lavish manner. But the native is only chewing Betel nuts, which have the power of turning the saliva red. The fruit is that of _Areca Catechu_, a fine palm which is cultivated, for this purpose only, in many parts of India and the East. The nuts are cut in pieces and rolled up with a little lime in leaves of the Betel pepper. It is said to turn the teeth red and sometimes to produce intoxication; at any rate, people become slaves to this disgusting habit, and they do not seem to be at all injured by indulgence in it. Another extraordinary plant is Henna (_Lawsonia inermis_). The Egyptian mummies are found to have the soles of the feet, as well as the palms and finger-and toe-nails, dyed a reddish-orange colour by the use of henna. But the practice is continued to-day in most parts of the East, and no odalisque's toilet would be considered complete without the use of henna. It is even said that men dye their beards with it. The white horse used in processions by the Shah of Persia has its legs, tail, and body dyed with henna. The powdered leaves are used: they are made into a paste with hot water, and then spread upon the place. It is grown in Syria, Egypt, Algeria, China, Morocco, Nubia, Guinea, and the East Indies. In China women dye their eyebrows with an extract of the petals of _Hibiscus Rosa-sinensis_. One of the first plants to be utilized by man was the Castor-oil (_Ricinus communis_). It was used by the Indians from time immemorial; it is mentioned by Herodotus (under the name Kiki); seeds have been found in mummy-cases, showing the careful preparations which were made for the dead when starting on their travels in the other world!