Lemons have been known for a long time. They were brought to the notice of the Greeks during the invasion of Alexander the Great into Media where the golden-yellow fruit attracted the attention of the warriors who gave them the name of Median apples (_Mala medica_). Later, Greek warriors also found this fruit in Persia, and hence named it Persian apples (_Mala persica_). The eminent Greek philosopher and naturalist Theophrastus, 390 B. C., described the fruit as inedible, though endowed with a fragrant odor, and having the power to keep away insects. On account of this latter property the so-called Median apple was, by some, supposed to be identical with the fruit of the cedar (_Kedros_) and therefore received the name "_Citrus_" from which is derived "citrone," the German name, and "citronnier," the French name for the fruit. Our word lemon is said to have been derived from the Indian word _limu_ and the Arabian word _limun_. It seems that at the time of the great Roman historian and naturalist, Pliny (23-79 A. D.), the lemon was not yet extensively cultivated. Dioscarides (50 A. D.) speaks highly of the medicinal virtues of the bitter and acrid wild-growing lemon. Cælius Aurelianus recommends lemon juice in gout and fevers. In 150 A. D., the lemon tree, evidently introduced, was found growing about Naples and in Sardinia, but the fruit was still inedible. About the third century cultivation had so far improved the fruit that it could be eaten. The Arabians are credited with first having introduced the lemon tree into southern Europe. The noted Arabian geographer, Edrisi, twelfth century, describes the lemon as very sour and about the size of an apple and the plant as growing only in India. This latter statement is, however, erroneous as the lemon had already been extensively cultivated in southern and eastern Spain, where it was introduced by the agriculturally-inclined Moors. It has been cultivated for many centuries in nearly all of the countries bordering on the Mediterranean Sea and is now also extensively cultivated in the tropical and sub-tropical countries and islands of the Western Hemisphere. One variety or species, (_Citrus lemetta_), is a native of the East Indies and is extensively cultivated in the West Indies. Lemon trees are found everywhere in the larger green houses and conservatories along with the closely related orange (_Citrus vulgaris_.) As the result of cultivation there are now about fifty varieties of lemons in existence. Some of these are comparatively sweet or rather insipid and are therefore known as sweet lemons. The sour varieties are, however, more generally cultivated. Lest I forget I will here state that the lemon is not identical, though closely related, with the Citron, the fruit of the _Citrus medica_.