Soldiers in war, or sailors upon long voyages, who are fed upon a diet consisting chiefly of salted or preserved meat, with bread or hard biscuit and sugar, but without either fruits or fresh vegetables, are likely to develop a disease called scurvy.

Little more than a century ago, hundreds of deaths occurred every year in the British and French navies from this disease, and the crews of many a long exploring voyage--like Captain Cook's--or of searchers for the North Pole, have been completely disabled or even destroyed entirely by scurvy.

It was discovered that by adding to the diet fruit, or fresh vegetables like cabbage or potatoes, scurvy could be entirely prevented, or cured.[10] Their Low Fuel Value.

How little real fuel value fruits and vegetables have, may be easily seen from the following table.

In order to get the nourishment contained in a pound loaf of bread, or a pound of roast beef, you would have to eat: 12 large apples or pears (5 lbs.); 4-1/2 qts.