Tea
Tea has refreshing and invigorating properties very comforting to one spent with toil. Its active principle is theine, a crystalline alkaloid found in both tea and coffee. Theine and caffeine were once supposed to be different substances, but have recently been found to be identical.
Tea is a valuable article of diet, though not a direct nutrient. It is classed with the so-called “accessory” foods, and, although not itself nutritious, aids, by its good flavor and stimulating properties, the digestion of other things. It is a nerve tonic, and is quite valuable as a curative agent for headache and some forms of indigestion. The slight stimulation resulting from its use is unattended by any after ill effects.
It is good for soldiers, hard-working people, travelers, and others who are much exposed to the rigors of climate.33