There is no certainty about the period at which lettuce was introduced into this country, although the time has been fixed at 1520, when it is stated to have been brought from Flanders. In the early part of the reign of Henry VIII., when Queen Katherine wished for a salad, she despatched a messenger to Holland or Flanders; at that period, therefore, very few English tables could ever boast the honour of a salad. In the privy purse expenses of Henry VIII., in 1530, an item occurs from which we learn that the gardener of York Place received a reward for bringing “lettuze” and cherries to Hampton Court. This was policy on the part of the King, his royal consort having a liking for salads, for it was rather expensive as well as tedious, to send for them to the gardens of Brabant.[22] In 1600, peas, beans, and lettuce were in common use in England; and in 1652, a writer of the time speaks of lettuce as a plant with which the public generally had been long familiar. One variety of the cultivated lettuce was doubtless derived from the island of Cos, inasmuch as it still bears that name.
Lettuces were known to the ancients. Dioscorides and Theophrastus speak of them as cultivated by the Greeks, and also used in medicine; the prickly lettuce is still found wild on the higher hills of Greece, and was probably one of the species to which the above-named ancient authors refer. Several varieties of the garden lettuce were used in salads by both Greeks and Romans. The pride of the garden of Aristoxenus was his lettuces, and he irrigated them with wine.
Two species of wild lettuce are found in Britain, the acrid and the prickly lettuce, both of which possess similar properties, yielding a juice from which lactucarium may be prepared. Two other wild species are only occasional. The lactucarium of the London Pharmacopœia is prepared only from the garden lettuce, but the acrid lettuce is stated to yield a much larger quantity and of superior quality. A single plant of the garden lettuce will yield only 17 grains of lactucarium, on an average, while a plant of the acrid lettuce yields no less than 56 grains, or more than three times that quantity; and although the milkiness of the juice increases till the very close of the time of flowering, or till the month of October in this climate, the value of the lactucarium is deteriorated after the middle of the period of flowering, for subsequently, while the juice becomes thicker, a material decrease takes place in the proportion of bitter extract contained in it.
Lactucarium is a reddish brown substance with a narcotic odour and bitter taste, having a considerable resemblance to opium. On analysis it yields a snow white crystalline substance called lactucin, which is narcotic in its effects. Dr. Duncan recommended the use of lactucarium as a substitute for opium, the anodyne properties of which it possesses, without being followed with the same injurious effects. In France, a water is distilled from lettuce, and used as a mild sedative. Experiments of the effects of lettuce-opium upon animals are detailed by Orfila, who states that three drachms introduced into the stomach of a dog killed it in two days, without causing any remarkable symptoms; two drachms applied to a wound in the back induced giddiness, slight sopor, and death in three days; and thirty-six grains injected, in a state of solution, into the jugular vein caused dulness, weakness, slight convulsions, and death in 18 minutes.
In North America the prickly lettuce is more common than with us, and from it the American lactucarium is extracted. In Guinea a species of lettuce is found wild, possessing precisely similar properties, and applicable to a like use. This plant is largely used by the negroes as a salad and also as an opiate.
The plants cultivated for the sake of the juice are grown in a rich soil, with a southern aspect. In such a situation they thrive vigorously, and send up thick, juicy, flower stems. As soon as these have attained a considerable height, and before the flowers expand, a portion of the top is cut off. The milky juice quickly exudes from the wound, while the heat of the sun renders it so viscid that, instead of flowing down, it concretes on the stem in a brownish flake. After it has acquired a proper consistence it is removed. As the juice closes up the vessels of the plant, another slice is taken off lower down the stem, and the juice again flows freely and another flake is formed. The same process is repeated as long as the plant affords any juice. To the crude juice, thus obtained, the name of lactucarium has been given.
“This,” says Johnston, “is one of those narcotics in which many of us unconsciously indulge. The eater of green lettuce as a salad, takes a portion of it in the juice of the leaves he swallows; and many of my readers, after this is pointed out to them, will discover that their heads are not unaffected after indulging copiously in a lettuce salad. Eaten at night, the lettuce causes sleep; eaten during the day, it soothes and calms and allays the tendency to nervous irritability. And yet the lover of lettuce would take it very much amiss if he were told that he ate his green leaves, partly at least, for the same reason as the Turk or the Chinaman takes his whiff from the tiny opium pipe: that, in short, he was little better than an opium-eater, and his purveyor than the opium smuggler on the coast of China.”
Lest this should occasion some alarm in the breasts of those who prefer their lobsters with a salad, let us strive to administer a little consolation. We have seen that the cultivated or garden lettuce does not contain so much as one third the quantity of lactucarium yielded by the wild species, ten good lettuces must therefore be eaten before sufficient extract will have been consumed to have killed a dog in two days. This is upon the presumption that the lettuces eaten as salad are in precisely the same condition, and capable of affording the same amount of the extract as when cultivated specially for that purpose; but this is not the case, it is not until just before flowering that the full amount of juice is contained in the plant, a per centage only of which exists in the younger plants as gathered for the table. Nor is that quantity of the same narcotic quality as in the more matured plant, which has collected, at that period, all its strength properly to produce, and bring to perfection, its flowers and fruit.
“Nothing hath got so far,
But man hath caught and kept it as his prey.