In washing flannels it is recommended that they should only be put into warm water, by which method their colour will be preserved, and they will be prevented from shrinking.

FLASH. Prep. From burnt-sugar colouring, 1 gall.; fluid extract of capsicum or essence of Cayenne, 34 pint, or enough to give a strong fiery taste. Used to colour spirits, and to give them a false strength. It is made by the brewers’ druggists, and labelled ‘ISINGLASS AND BURNT SUGAR,’

FLASKS. The late lamented and ingenious Mr Fownes suggested the employment of Florence oil-flasks as cheap substitutes for retorts, receivers, digesters, and some other vessels used for chemical purposes. His plan was to cut the neck smoothly round with a hot iron, and softening it in the flame of a good argand gas-lamp, to turn over the edge so as to form a lip, or border. The neck will then bear a tight-fitting cork without splitting.

FLATULENCE. Syn. Flatulency, Wind. In pathology, a morbid collection of gas in the stomach and bowels. Its most common cause is indigestion. When the natural fluids of the stomach are secreted in a healthy state, they exercise an antiseptic and digestive action on the food, by which it is speedily reduced to a magma that is little liable to spontaneous change whilst in the body; but when the reverse is the case, fermentation soon commences, and the stomach and associated viscera become distended with gas, and all the well-known symptoms of flatulency are developed in rapid succession. The quantity of gas thus accumulated in the ‘primæ viæ’ is often enormous. An ordinary apple during fermentation yields about 600 times its bulk of gas, and many vegetables yield much more. (Dr Hales.) It is, therefore, not at all surprising that so much inconvenience should be felt when the food, instead of being digested and assimilated, runs into the state of active fermentation.

The treatment of flatulency consists mainly in the selection of proper articles of food. Oleraceous vegetables, peas, beans, under-dressed potatoes, and indigestible fruits should be especially avoided, as well as the use of large quantities of weak or warm liquids. The diet should consist principally of animal food, carefully but not over-cooked, with a sufficient quantity of good mealy potatoes (mashed, not whole), and good wheaten meal-bread, moderately seasoned with common salt and spices. The most suitable beverages are toast-and-water, and a little good brandy largely diluted with water. The healthy tone of the stomach may be re-established by the proper use of tonics, bitters, and mild aperients.

To relieve the fit of flatulency, carminatives and aromatics, as black pepper, mustard, peppermint, ginger, cinnamon, lavender, and most spices, may be had recourse to. A glass of peppermint cordial, or of brandy strongly flavoured with peppermint or ginger, is a popular and efficient remedy. A few drops (15 to 30) of ether, with a little tincture of capsicum or spirit of sal volatile, seldom fail to give relief. See Dyspepsia.

FLAVOURING SUBSTANCES. See Essence, Oil (Volatile), Spice, Wine, &c.

FLAX. See Linen, Linseed, and Oil.

FLEA. This troublesome little animal is the Pulex irritans of Linnæus, and belongs to the Suctoria, or fourth order of the Insecta. Its favorite haunts are our warm underclothing, and its most productive breeding-places are in the ‘flue’ which careless servants allow to accumulate underneath our beds. Cold, light, perfumes, and ventilation, are inimical to its propagation.

FLECHTENKAPSELN (Tetter Capsules, or Dr Berkeley’s Antiherpetic Capsules for Skin