Ringworm

“ Short, stout hair of beard, with the root-sheath attached, showing free spores and chains of spores.
To what is ringworm due?
To the presence and growth in the cutaneous structures of a vegetable parasite. Although the disease is contagious, individuals differ considerably as to susceptibility. It is much more common in [Pg 258] children than in those past the age of puberty, ringworm of the scalp being limited to the former (rare exceptions) , and tinea sycosis being a disease of the male adult. ”

“ Absence of trichophyton elements and of a well-defined, slightly raised, festooned, and itching margin, together with the presence of large blebs and scaling of the epidermis, distinguish it from ordinary forms of body ringworm— a disease with which, when occurring in the armpits and crutch in adults, it is frequently confounded. ”

“ By applying a cover glass with firm pressure the epidermal cells are spread out and the parasites can be seen, especially around the roots of the hairs. Sometimes they form little dirty-yellow masses, consisting almost exclusively of spores.
When ringworm has attacked the entire surface of the body, it is much more difficult to distinguish from sebaceous eczema, and a microscopic examination or experimental inoculation may become necessary. Inoculation with ringworm material always succeeds with calves.
Prognosis. Ringworm is not dangerous in itself. ”

“ The superficial type of ringworm sycosis—those cases in which the disease remains a surface disease—is readily distinguished, as the symptoms are essentially the same as ringworm of non-hairy parts, except that some of the hairs in the areas may become invaded and break off or fall out. ”

“ On looking closely it will be seen that the hairs have been broken off short, close to the skin, but are clearly visible, which is the chief feature of the disease and the infallible sign. Ringworm may be caught at any time, most frequently from a visit to some infested stable, but occasionally from chance contagion in the streets. Horses are subject to the same form of the complaint, and dogs generally catch it from them; it is sporadic, and the spores may, of course, fall about anywhere from an infected horse or another dog. ”

“ The treatment of ringworm consists in shaving the part, and keeping it clean with soap and water, at the same time that an occasional mild saline aperient is administered, and a light, nutritious diet, of which the red meat and ripe fruits should form a portion, be rigorously adhered to. When the scabbing commences, dressings of tar ointment, or of the ointment of nitrate or red oxide of mercury, or a mixture of equal parts of the first and either the second or third, should be applied, in each case diluting the mixture with sufficient lard to adapt it to the state of irritability of the part. ”

“ Common ringworm, or Tinea tonsurans, is very contagious, making itself manifest by the hair of the head becoming thinner, more fragile, less colored than the surrounding hairs. The affected hairs are apt to turn reddish or ashy-gray ”

“ A saturated solution (1 in 1000 of warm water) , thymol gauze and an ointment are used. Externally it is antiparasitic, and is used in certain stages of eczema and psoriasis, and the alcoholic solution has been used in ringworm; internally it has been employed as an intestinal antiseptic in typhoid fever. Its chief use is as an anthelmintic to destroy the Ankylostoma duodenale. Thymol may colour the urine green. Thymol iodide, official in the United States, is a compound of iodine and thymol ”

“ There is yet another Filarian worm, a pest to the poultry-yard, the Gape-worm, Sclerostoma syngamus. This parasite is widely distributed, and is invested with special interest, since it produces disease, and kills annually thousands of young chickens, pheasants, partridges, and many of the larger kinds of wild birds. The worms find their way into the windpipe or tracheæ, through the drinking water, while in the embryotic or cercarian stage of existence, and their increase is so rapid, the birds quickly die of suffocation. ”

“ Another species of thread-worm (Filaria lacrymalis) is occasionally found in the horse between the lids and eyeball. It is a comparatively small and harmless parasite, the males measuring 1/2′′ in length and the females 2/3′′. It also infests the ox. Both the large and small eye-worms are viviparous, and, not improbably, both of them are the means of conveying embryonic Filariæ into the circulation. Be this as it may, we owe to Dr Sonsino the discovery of hæmatozoa in an Egyptian horse. The larval worm was provisionally named by him Filaria sanguinis equi. ”

“ I need only mention the canker worm and American tent caterpillar, and the various kinds of cut worms, as instances.
43. Parasite of the American Silk Worm.
We must not, however, forget the good done by insects. They undoubtedly tend by their attacks to prevent an undue growth of vegetation. The pruning done to a tree or herb by certain insects undoubtedly causes a more healthy growth of the branches and leaves, and ultimately a greater production fruit. Again, as pollen-bearers, insects are a most powerful agency in nature. ”

“ Not only unicellular organisms, such as bacteria and protozoa, but also the eggs, embryos and larvæ of parasitic worms have been found to be transported by house-flies. Ransom (1911) has found that Habronema muscæ, a nematode worm often found in adult flies, is the immature stage of a parasite occurring in the stomach of the horse. The eggs or embryos passing out with the feces of the horse, are taken up by fly larvæ and carried over to the imago stage. ”

“ The colour is saturated green, the eyes are transformed into round, projecting shiny black beads, and the head is erect. The ludicrously dreamy, complacent look has given way to wide-awake alertness. They take all kinds of living food. When they find an earthworm, they first look at it, bending the head sharply down, lift themselves upon the fore-limbs and then pounce upon it, nipping the prey with the jaws, and then poking it down deliberately with the hands. ”

“ Others, and this is the most common mode of parasitism, attack the insect in its larva state; others, in the pupa state, and still others in the perfect, or imago state. Dr. Leidy has shown that the wood-devouring species of beetle, Passalus cornutus, and some Myriopods, or "thousand legs," are, in some cases, tenanted by myriads of microscopic plants and worms which luxuriate in the alimentary canal, while the "caterpillar-fungus" attacks sickly caterpillars, filling out their bodies, and sending out shoots into the air, so that the insect looks as if transformed into a vegetable. ”

“ The female glow-worm, the light-giver, is wingless; the male is winged. The latter, however, has but little of the light emitting power possessed by the female. Only the light-givers are collected, and being destitute of the first attribute of an insect, wings, are set down in popular parlance as worms. Old mossy banks, damp hedgerows, and shaded woods are the loved haunts of the fireflies, and the warm nights of the soft summer months most induce them to burn their soft lustre. Some widowed worm or firefly flirt may shed her luminous self in the darkness even on into dying summer or autumn. ”

“ Once such an insect is caught on one of the threads it is lost beyond all hope. There it sticks, struggle as it may. The vibrations caused by its struggles attract the attention of the glow worm which quickly winds up the hanging thread. If it is not hungry at the moment it has been observed to play with its victim, [Pg 5] drawing in and then letting out the line after the manner of a fisherman. Finally the prey is drawn into the silken sheath and entirely devoured, chitinous shell and all. It is not merely sucked, as is the fashion of the spider or the fly. ”

“ The very name Earthworm, so distinctive as it is of the habitat of these animals, seems to have been expressly invented in order to crystallise into one word the remarkable distributions of these creatures. They are with very few exceptions the most purely terrestrial animals that we know. There are a few Mammals like the mole and several underground Amphibians and Snakes in the tropics which share this habitat with the worms, probably because they chiefly prey upon them. But there is no group of animals that is characterised by a subterranean existence in the way that earthworms are. ”

“ Here the worm, always lodged in the intestines, grows with extraordinary rapidity, and fulfils all the conditions of a true parasite. In a fertile soil it extends itself and produces young as long as it has any life, and in no group of the animal kingdom do we find any fecundity to be compared to that of this worm. Boerhaave described a broad tape-worm, three hundred ells in length. ”

“ The presence of these parasites finally exhausts the host, so that the sterile female bee dies prematurely.
41. Bee fungus.
As in the higher animals, bees are afflicted with parasitic worms which induce disease and sometimes death. The well-known hair worm, Gordius, is an insect parasite. The adult form is about the size of a slender knitting needle, and is seen in moist soil and in pools. It lays, according to Dr. Leidy, "millions of eggs connected together in long cords." The mi [Pg 47] croscopical, tadpole-shaped young penetrate into the bodies of insects frequenting damp localities. ”

“ Some doubts have occurred as to the food of the glow-worm. From actual observation, it has been ascertained that its larvæ feed on snails, decayed worms, &c., and are decidedly carnivorous. Neither old nor young touch plants as food. The larvæ are very voracious in their habits; but it is supposed that the perfect insect eats but little. If it does eat, it probably feeds on animal substance.
The female is without wings, and is far more luminous than the male. ”

“ As they leave the bodies of their hosts they fall to the ground, and crawl away into the deeper and moister parts of the soil. Threadworms found in the damp earth, in digging up gardens and cutting ditches, have often been brought to me, which presented no external distinctions from the threadworms of insects. This suggested to me that the wandering threadworms of insects might instinctively bury themselves in damp ground, and I therefore instituted a series of experiments by placing the newly-emigrated worms in flower-pots filled with damp earth. ”

“ Very good illustrations of this kind of work are afforded by the rascal leaf-crumpler and the common bag worm, both of which in the larva state live in cases, and are much affected by parasites, and neither of which can survive if the cases are plucked in winter and placed away from any trees or shrubs, while under these circumstances the parasites will perfect and escape.
It is quite different with the second method of dealing with beneficial insects which I have mentioned, for here man has an opportunity of doing some very effective work. ”

“ The roundworms are slender, smooth, cylindrical worms pointed at both ends. They are all very long in proportion to their diameter, although their actual length may be short. Some species are of microscopic size; as the Trichina worm, which is about 1/20 in. long; while the guinea-worm, one of the worst parasites of man, may reach a length of six feet. Many of the roundworms are parasites living in the various organs of other animals. Some, however, lead an independent free life in water or in damp earth. ”

“ Between these two extremes we find various transitional forms: an active larva, as described above, but with four-segmented, single-clawed legs, as among the rove-beetles and their allies; the body well armoured, but slender and worm-like, with very short legs as in wireworms and mealworms (figs. 18, 21 b) ; the body shortened, with the abdomen swollen, but protected with tubercles and spines, and with longish legs adapted for an active life, as in the predaceous larvae of ladybirds ”

“ Among the Coleoptera or beetles there is a group of world-wide pests, the Elateridae or click beetles, the adults of the various “wireworms.” The insects in the larval or wireworm stage attack the roots of plants, eating them away below the ground. The eggs deposited by the beetle in the ground develop into yellowish-brown wire-like grubs with six legs on the first three segments and a ventral prominence on the anal segment. The life of these subterranean pests differs in the various species ”

“ One of the most unusual of all luminous creatures is an insect larva found by farmers ploughing damp soil in Brazil and Uruguay. It is a reddish-brown little worm with rows of green lights on both sides and a vivid red lamp on the front of its head. The red light is actually red—not white light shining through a reddish skin. Adult females of the species retain the same luminous pattern. Male adults have only feeble, yellow lights. The larva are extremely vicious little creatures, predators on white grubs which infest the soil. ”

“ During the day they remain in their burrows, except at the pairing season, when those which inhabit adjoining burrows expose the greater part of their bodies for an hour or two in the early morning. Sick individuals, which are generally affected by the parasitic larvæe of a fly, must also be excepted, as they wander about during the day and die on the surface. After heavy rain succeeding dry weather, an astonishing number of dead worms may sometimes be seen lying on the ground. ”