A lotion of corrosive sublimate, one to four grains to the ounce; infusion of tobacco; a ten to twenty per cent. ointment of oleate of mercury; ammoniated mercury ointment, and a five to ten per cent.

[beta]-naphthol ointment. Repeated washings with vinegar or dilute acetic acid, or with alkaline lotions, will free the hairs of the ova.

Cysticercus Cellulosae.

Describe the cutaneous disturbance produced by the cysticercus cellulosae.

The presence of cysticerci in the skin and subcutaneous tissue gives rise to pea to hazelnut-sized, rounded, firm, movable tumors which, when developed, may remain unchanged for months. The parasites are disclosed by microscopic examination.

Most of the cases have been observed in Germany.

Filaria Medinensis.

(_Synonym:_ Guinea-worm.)

State the character of the lesions produced by the filaria medinensis.

The young microscopic worm penetrates the skin or deeper tissue, where it grows gradually, finally reaching several inches or more in length and about a half-line in thickness; inflammation is excited and a tumor-like swelling makes its appearance, which, sooner or later, breaks, disclosing the worm. It may also present a cord-like appearance.

It is rarely met with outside of tropical countries.

Treatment consists in gradual extraction, or in the injection of a corrosive sublimate solution (1:1000) into the forming tumor. Asafetida internally has been found to be curative, the parasite being destroyed and subsequently absorbed or discharged.

Ixodes.

(_Synonym:_ Wood-tick.)

State the character of the cutaneous disturbance produced by the ixodes.

The tick sticks its proboscis into the skin and sucks blood until it is several times its natural size, and then falls off; an urticarial lesion results. If caught in the act the animal should not be forcibly extracted, as its proboscis may be thus broken off and remain in the skin, and give rise to pain and inflammation. It may be made to relinquish its hold by placing on it a drop of an essential oil.

A thymol or carbolized boric-acid lotion will relieve the irritation.

Leptus.

(_Synonym:_ Harvest-mite.)

State the characters of the lesion produced by the leptus.

This minute brick-red mite buries itself in the skin, especially about the ankles and feet, giving rise to papules, vesicles and pustules.

Treatment consists of the use of a mild sulphur ointment or of a carbolic-acid lotion.

[OE]strus.

(_Synonym:_ Gad, or Bot-fly.)

Describe the cutaneous disturbance produced by the [oe]strus.

The ova are deposited in the skin, develop and give rise to the formation of furuncle-like tumors with central aperture, through which a sanious discharge exudes; or as the result of the burrowing of the larvae, irregular serpiginous lines or wheals are produced.

It is chiefly met with in Central and South America.

_Larva migrant_, or _creeping disease_, is doubtless in this same cla.s.s.

It is characterized by a thread-like linear formation of an erythematous, erythemato-papular, or vesicular nature that gradually extends, the older part disappearing; considerable surface may be covered before the parasite disappears or dies. The treatment consists in endeavoring to destroy the organism by means of excision or caustic applications at the point of its suspected site which is just ahead of the extending line.

Pulex Penetrans.

(_Synonyms:_ Sand Flea; Jigger.)

Describe the cutaneous disturbance produced by the pulex penetrans.

This microscopic animal penetrates the skin, especially about the toes, producing an inflammatory swelling, vesicle or pustule, or even ulceration. It is met with in warm and tropical countries.

Treatment consists in extraction. Essential oils are used as a preventive. A carbolic-acid or alkaline lotion relieves irritation.

Cimex Lectularius.

(_Synonym:_ Bed-bug.)

Describe the characters of a bed-bug bite.

An inflammatory papule or wheal-like lesion results, somewhat hemorrhagic; the purpuric or hemorrhagic point or spot remains after the swelling subsides, but finally, in the course of several days or a few weeks, disappears.

Treatment consists in the application of alkaline or acid lotions.

Culex.

(_Synonym:_ Gnat; Mosquito.)

Describe the cutaneous disturbance produced by the culex.

It consists of an erythematous spot or a wheal-like lesion.