The male insects run about on the surface.
Fig. 168 represents a female scams at the end of its burrow and a series of eggs be hind it.
. Symptoms. — The L disease usually tacks the webs tween the fingers, the front of the wrists and elbows, and the lower part of the belly, the nipple in the female, the buttocks, and the genitals. The feet and legs are attacked in children. There is intense itching, worse at night, or whenever the person becomes warm. The scratching induced, as well as the irritation excited by the burrowing of the parasites, leads to a scattered inflammation of the skin ; swollen lines, pimples capped with crusts of dried blood, blisters and pustules are formed. The chief thing to be looked for is the burrow, which is like an old pin-scratch. It is irregular in shape, from half a line to 3 inches long, with a whitish dotted appearance, the dots being the eggs, and a little mound at the deep end, where the adult acarus lies. If all the canal has been opened up it may simply appear as a dirty ragged line.
Treatment is simple and effective. The affected person should take a hot bath, and should thoroughly scrub the whole body, except the head, with soap and water. Persons with thick and not very sensitive skin may use soft soap. After the bath the whole body, and especially the parts where the eruption is, must be well anointed with sulphur ointment, either the simple or compound sulphur oint ment of druggists. The ointment should be well rubbed in. If it is properly done, one application is sufficient. An ointment may be made of subcarbonate of potash (1 drachm), sulphur (2 drachms), and lard (12 drachms). In the morning after the use of the ointment a warm bath should be taken. To destroy in sects on the person's clothes they should he steeped in boiling water, or exposed for some time to air at a temperature of 150° Fahren heit, or ironed thoroughly all over with hot irons.
Lousiness (Phtlairiasis).—Three kinds of lice may be harboured on the human body—the head-louse (Pediculus capitis), the body louse (Pediculus corporis), and the louse found on hairy parts except the head, and specially on the pubis— the crab-louse (Pediculus pubis), each kind limiting itself to its special region of the body. The head-louse is shown in Fig.
169. It has a body of seven segments, an oval head, pro vided with feelers (antennae), and six legs, three on each side, which are hairy, and ter minate in claws. The head has two simple eye:. and is provided with biting and sucking apparatus. The animal is able to bite into the skin and then to insert its proboscis into the wound in order to suck blood. The head-louse confines itself to the scalp, running about amongst the hairs, where it is capable of mul tiplying with great rapidity by means of eggs. The eggs (nits) are firmly attached to the hairs by means of sheaths, and from them the young escape at the end of nine days, and are fully developed at the end of eighteen. The lice are found in greatest abundance in the back and aide portions of the head. "A single louse may lay fifty eggs within six days, which may he hatched in from three to eight days. The `young ones' are capable of laying eggs them selves in another eighteen days or three weeks. A pregnant louse, therefore, may be the means of bringing forth some 5000 young ones in the course of eight weeks" (Professor Hebra). In women and children, because of their long hair, lice are more common than in men.
Very severe symptoms may be produced by the insects. Their biting irritates and wounds the skin. It also renders the skin itchy, and the person scratches. Between the two an in flammation of the skin is produced, an eczema (p. 425). The skin is torn with scratching, and blood escapes, which dries into crusts. An eruption of blisters of the size of a pin's head or a pea appears. These are torn and weeping, ' and the fluid dries up also into crusts. Beneath the crusts matter forms, and the hair becomes matted together and covered with nits. This condition of things, if not promptly attended to, spreads, and a foul, matted mass of scab and entangled hair is produced, among which the lice continue to breed. On the neck, but les selling from above downwards, scratches, pus tules, &c., also are present, and the ears may be affected. The glands of the neck readily become swollen, and often in children swollen and running glands in the neck are due entirely to the irritation of such a condition of affairs in the head (see p. 284).