Men are often placed under conditions in which, from poverty or exposure, sufficient quantities of food cannot be obtained. Under these circumstances, the craving of hunger may be diminished and the actual tissue waste may be retarded by the substitution of certain mild stimulants and beverages. Tea, coffee, and tobacco all possess moderate action in this respect, and alcohol, under such conditions, is both a stimulant and a food. The natives of various barbarous or semicivilised countries, while performing long feats of marching, being often unable to obtain sufficient food with regularity, make use of a variety of different substances for the purpose above indicated. Among these may be mentioned betel nut, kola nut, Siberian fungus, the cocoa leaf, and pepperwort, which are chewed from time to time; hasheesh and opium, which are both eaten and smoked; mate, and various forms of alcoholic fermented drinks. All these substances are used to enable men to prolong periods of fasting.