In the days of sailing ships, fresh food was unavailable on board, and at the end of long voyages many sailors would contract scurvy, a potentially life-threatening condition. Today we recognize ascorbic acid as a cure for this condition, but in the late seventeenth and early eighteenth century medical practitioners and scientists had no such surety. Shakespeare’s son-in-law, the seventeenth-century herbalist and surgeon John Hall, cured several cases of scurvy by administering an acidic brew composed of brooklime, scurvy grass and watercress, all herbs rich in ascorbic acid. The celebrated physician William Harvey suggested that sailors take lemon juice to ward off scurvy; he hypothesized that citric acid, the specific acid in lemon juice, would prevent the disease. In the mid-eighteenth century, the Scottish naval surgeon James Lind conducted an experiment involving 12 sick sailors to discover whether the acid was responsible for the cure. All of the sailors received the same diet except that in addition each day two of the men were given small amounts of dilute sulfuric acid, two others some spoonfuls of vinegar (acetic acid), two more a quart of cider, two more half a pint of seawater, two more a paste of spices with some barley water, and the remaining two a lemon and two oranges. Only those given the lemon and oranges recovered from the disease.
As used in the passage, "contract" most nearly means
Asettle by agreement
Bbe drawn together
Dbecome affected by
Ereduce in compass