Chemically the wild Lettuce contains lactucin, lactucopricin, asparagin, mannite, albumen, gum, and resin, together with oxalic, malic, and citric acids; thus possessing virtues for easing pain, and inducing sleep. The cultivated Lettuce which comes to our tables retains these same properties, but in a very modified degree, since the formidable principles have become as completely toned down and guileless in the garden product as were the child-like manners and the pensive smile of Bret Harte's Heathen Chinee.
Each plant derives its name, lactuca, from its milky juice; in Latin lactis; and in Greek, galaktos (taking the genitive case). This juice, when withdrawn from the cut or incised stalks and stems of the wild Lettuce, is milky at first, and afterwards becomes brown, like opium, being then known (when dried into a kind of gum) as lactucarium. From three to eight grains of this gum, if taken at bedtime, will allay the wakefulness which follows over-excitement of brain. A similar lactucarium, got from the dried milk of the cultivated garden Lettuce, is so mild a sedative as to be suitable for restless infants; and two grains thereof may be safely given to a young child for soothing it to sleep.
The wild Lettuce is rather laxative; with which view a decoction of the leaves is sometimes taken as a drink [308] to remedy constipation, and intestinal difficulties, as also to allay feverish pains. The plant was mentioned as acting thus in an epigram by Martial (Libr. VI., Sq.).
"Prima tibi dabitur ventro lactuca movendo
Utilis, et porris fila resecta suis."
Gerard said: "Being in some degree laxative and aperient, the cultivated Lettuce is very proper for hot bilious dispositions;" and Parkinson adds (1640): "Lettuce eaten raw or boyled, helpeth to loosen the belly, and the boyled more than the raw." It was known as the "Milk Plant" to Dioscorides and Theophrastus, and was much esteemed by the Romans to be eaten after a debauch of wine, or as a sedative for inducing sleep. But a prejudice against it was entertained for a time as venerem enervans, and therefore mortuorum cibi, "food for the dead."
Apuleius says, that when the eagle desires to fly to a great height, and to get a clear view of the extensive prospect below him, he first plucks a leaf of the wild Lettuce and touches his eyes with the juice thereof, by which means he obtains the widest perspicuity of vision. "Dicunt aquilam quum in altum volare voluerit ut prospiciat rerum naturas lactucoe sylvaticoe folium evellere et succo ejus sibi oculos tangere, et maximam inde claritudinem accipere."
After the death of Adonis, Venus is related to have thrown herself on a bed of lettuces to assuage her grief. "In lactucâ occultatum a Venere Adonin—cecinit Callimachus—quod allegoricé interpretatus Athenoeus illuc referendum putat quod in venerem hebetiores fiunt lactucas vescentes assidue."
The Pythagoreans called this plant "the Eunuch"; and there is a saying in Surrey, "O'er much Lettuce in [309] the garden will stop a young wife's bearing." During the middle ages it was thought an evil spirit lurked among the Lettuces adverse to mothers, and causing grievous ills to new-born infants.
The Romans, in the reign of Domitian, had the lettuce prepared with eggs, and served with the last course at their tables, so as to stimulate their appetites afresh. Martial wonders that it had since then become customary to take it rather at the beginning of the meal:—
"Claudere quae caenas lactuca solebat avorum
Dic mihi cur nostras inchoat illa dapes."