PARASITIC DISEASES OF THE SKIN.

Otago Witness, Issue 2527, 20 August 1902, Page 6

PARASITIC DISEASES OF THE SKIN.

Certain minute animals and plants find & congen.al habitat on or in the f-kins of other anirrals and plants larger and more highly organised than themselves, and, while securing their own maintenance, often damage to a greater or less extent tho tissues of their hosts, as the infested animals are called. Some parasites, however, . are content to remain upon the surface of tha skin, and — so writes a veterinary authority, in the Field — "even live upon the waste tissues, thus doing good, as far as scavengers can be said to act usefully in the disposal of effete material." Most of the parasitic plants and animals in their search for food induce some changes in the tissues whirl* they invade, and the dermatologist recognises the importance of identifying the microscopic beings which are the causes of many forms of slain disease, in order to effect their destruction by the use of agents which are capable of killing them by merQ contact, or otherwise by rendering the. tissues they invade unfit for their residence. In forming an opinion of the nature of a« eruptive affection, the pathologist almost;

A» the season is now approaching for the Bowing of winter wheats, farmers should use Nnnto and Blaib's "Standard Grattj.' Manure, which will udd bushel* of graiA per acre to their crops. It is a manor© p£ very high quality, and always gives oati*«

"as a matter of necessity takes into consideration the probability of parasites being present, and the diagnosis is, or should be, 1 'based on the identification of the parasites, wLich, with few exceptions, are invisible to 'the tinaided eye; while some of them can "only be seen by the assistance of a magnifying power of one to two btmdred diameters at the least. Diseases of tho skin due to parasites are admitted to be contagious. It must, however, be remembered that the term in £uch cases has a limited meaning. Parasitic diseases arc contagious only as the result of the migration of the parasites from a diseased to a healthy subject. FOl an example, the common conditions known as lousiness may be. referred to. Lice of various kinds attach themselves to the skin, and cause an excessive degree of irritation by biting or wandering over the surface. I/ice are always associated with poverty sfhd dirt, and their presence may be accepted as evidence- of neglect, which is the more remarkable when cattle are tho victim?. The constant itching which is one_of the immediate results of tho presence of the creatures in any considerable numbers interferes with the animal's condition, and, in severe cases prevents feeding or resting. Cattle, not being, a3 a rule, regularly groomed, aro much more likely than horses to suffer irom lico, and the continued ravages of the insects lead to development of diseases of the skin that are not easily cured and cannot even be relieved until the parasites are destroyed by the use of active remedies, which must necessarily increase the irritation for at least come time. Even among young stock the existence of lice is highly injurious, and it would be found economical to rid them of the parasites, oven at some cost, rather than allow the stock to loso condition from the constant irritation and restlessness which are incidental to the presence of the peste. Remedies cannot bo expected to act effectually unless the affected cattle are placed under favourable conditions in regard to cleanliness and good management, inclinling a sufficiency of nutritive food. Parasites, both animal and vegetable, exhibit a decided preference for young ar.d weaWy subjects, and they also find in dirty, half-ruined sheds and stables exactly tha surroundings ■which suit them, so that a serious attempt to banish the invaders must include a thorough cleansing of the* places in which the diseased or infested cattle have boen loept before local remedies can be successfully applied. Young animals which are Kept en pasture lands, eFpecially in the neiuhbournood of bushes, are very likely to become lousy, and it is seldom that any notice is taken until the cattle are- brought up for winter, and then it will not be thought necessary or desirable to destroy tho pa.' asites with which they are infested. A Htilo consideration would, however, convince tho stockowner that the destruction of the- paraeite is essential to the well-being of tho stock. Of the remedies that are used for killing lice 021 th# skin, mercurial preparations are most effective, but they are alao most dangerous, and should only be employed by skilful persons. Ordinary blue mercurial ointment, mixed with oil to form a thin creamy fluid, may be used in very bad cases by running it sparingly along tho back and sides after dividing the hair from head to, tail by means of a blunt-pointed knifo or other instrument. A small quantity of the mixture must then bo carefully applied along the lines by means of a =tiff brush, and in the course of sue or eight hours the entire skin should be well washed with warm water •with soft soap. Probably one dressing and washing, if properly done, will destroy all the living lice on the infested animal, but the "nits (eggs) will most of them escape, and in a few days the younc lice will be hatched, and soon acquire all the powers of annoyance possessed by their parent- 5 . To avert this result it is necessary to repeat the dressing in 10 days to a fortnight, and it may be desirable in the case of very young animals to us» a more diluted form of the mixture than that which was employed for the firfat dressing. When mercurial dressings are not used, a, preparation of sulphur in fine powder mixed with oil to the consistency of cream is ft safe agent, which may be used repeatedly without danger. Washing with soft soap and wa-rm water should never be omitted, no matter what dressing may be selected. Infusion of tobacco is a very potent means of destroying lice, but care must be taken not to use the infusion too strong, as the narcotic action is sometimes very pronounced. The effects of tobacco ■water are sufficiently rapid to allow the ■washing with soft «=oap and warm water to take place a couple of hours or le=s after the dressing, and, as was suggested in the use of mercurial dressing, it is nccessaiy to repeat the remedy in order to destroy the young brood which will be set free from numerous eges, which escape the action of remedies used.

Older animals affected with lice-, hordes ©specially, may be dealt with in a summary manner by clipping or singeing, but even theeo means cannot be relied on to clear off ail the parasites at once, and, to make all safe, a mixture of one part of carbolio acid to 50 parts of warm water, to which soft soap has been added in sufficient quantity to mako a whito and smooth emulsion, may be applied freely over the whole body, *o be followed in an hour or -two by a thorough washing. It may be added that

lousiness is unknown in a well-managed stable. The same thing cannot bo said n> reference to cattle, because it is not an uncommon thing to find cattle that have been prepared for exhibition suffering from tbo parasites, which have be-on evidently left undisturbed for months, leaving the infested animal a sourco of danger to all others with which it may come in contact in its journey ings. A curious characteristic of parasites deserves to be specially noticed. Each variety of parasite shows a mar.red preference for the Fkin of a. particular "species of animal, on the skin of which it will live and flourish: but if transferred to the skin of another species, it will either die or migrate to another habitat. Thus, lice of the horse will not take kindly to the skins of cattle, and so with regard to the different domestic breeds — each has its own variety of parasites Expeiiments, however, have proved that under so mo exceptional conditions the paiasites of ono specie* of animal will live for some tune on animals, of different species.