_Wingless Pests._—_Lice._—These are known to transmit typhus fever. Further, they often cause great cutaneous irritation and are loathsome companions. It is no easy matter to get rid of lice when infection is on a large scale, but very often this is not the case and it is possible to detect their presence only by careful examination. There is no real difference between head lice and body lice; they are simply varieties of the same insect. The presence of head lice may be recognized by the discovery of their eggs, which are known as nits and are minute, yellowish-white, goblet-shaped bodies about the size of a full-stop on this page. Examination for head lice is much facilitated by the use of a fine tooth comb. Persons suspected of harbouring body lice should be examined first for the actual bites of the insect on the skin. Their clothes, and especially their under-garments, should then be carefully examined, attention being more particularly directed to the seams and folds where the eggs, if present, are most likely to be found. The best preventive measure against lice is strict personal cleanliness. Clothes should be frequently changed, and as frequently washed. The hair should be kept cropped short, especially at the sides and back of the head, and in the tropics it is very advisable to shave all hairy parts of the body. Space does not permit a full account of how to deal with verminous persons and verminous clothing, but it may be said that the only reliable methods of destroying lice are by hot air, steam, boiling water, or hydrocyanic acid gas. At the same time it should be noted that the heads of those infested with head lice should be thoroughly combed and treated with paraffin, petrol, or white precipitate ointment, and then well washed with carbolic soap. The nits may be loosened by treatment with warm vinegar or acetic acid. In the case of body lice possibly the most satisfactory grease for application to the underclothing is one composed of crude unwhizzed naphthalene from the coke oven, four parts, and soft soap, one part. It is important that the proper type of naphthalene be used. A useful palliative method is the ironing of clothing, especially along the seams, with heavy hot irons. _Fleas._—Bubonic plague is known to be transmitted by fleas, and it is possible that they play a part in the transmission of that form of leishmaniasis which is known as kala-azar (_see_ p. 202). Fleas dislike powdered naphthalene and pyrethrum powder, and either of these may be applied to the clothes to ward them off. A note on the troublesome _Chigger flea_ or _Jigger_ will be found under “Skin Diseases” (_see_ p. 228).