General Remarks

In describing the disorders caused by tapeworms it is best to include the taenia solium, taenia mediocanellata, and bothriocephalus latus.

The symptoms produced by these three different entozoa are almost identical. In some instances the tapeworm is domiciled in the intestine for a long period of time without manifesting any symptoms. The host may enjoy perfeet health and only after noticing segments of taenia in the dejecta does he become conscious of his uninvited guest. In other instances the worm produces intestinal as well as general disturbances. A feeling of pressure at the pit of the stomach and pains at different points of the abdomen may be present. Bulimia is frequently encountered. Anorexia and anorexia alternating with bulimia are also occasionally observed. Nausea, even vomiting, may be present, especially in the morning. The bowels are usually constipated. In a few instances, however, there is persistent diarrhoea.

1 Malmsten: Virchow'a Archiv. Bd. xii.

Besides these gastro-intestinal symptoms there may be present various disturbances of the nervous system or of the blood; dizziness, headache, fainting spells, convulsions, epilepsy, various forms of paraesthesia of the extremities. Some patients, again, look very bad and become emaciated, notwithstanding that they take sufficient quantities of food. The anaemic condition is occasionally very marked. The patient feels extremely weak, suffers from palpitation of the heart, is hardly able to walk, and is subject to fainting spells. In this serious form of anaemia oedema of the feet and eyelids may exist as well as hemorrhages from the mucous membranes. The microscopical examination of the blood in these instances reveals poikilocytosis and also nucleated red blood corpuscles, thus demonstrating the existence of a progressive pernicious anaemia. The grave condition just described has been observed only in the presence of bothriocephalus latus but not of the other varieties of tapeworms.

The proof that the symptoms described are produced by the tapeworm is found in the circumstance that they disappear entirely after the removal of the parasite.

None of the above symptoms, however, permits the diagnosis of tapeworm, for they are found also when it is not present. The diagnosis can be made only by the discovery of either segments of the parasite or their eggs in the stools.

The tapeworm has a head or scolex, which may remain alive for years, - even when separated from the other part of the body, - an oblong neck and detachable segments (proglottides). The latter vary in size and in configuration the farther away from the head they are situated. They possess the power of moving. The tapeworm is a fiat worm devoid of mouth or intestine. It grows by alternate generation through the germination of a pear-shaped primary host (head) and remains united with the latter for a considerable time as a long band-shaped colony. Each member of the colony forms a sexually active individual. The proglottides increase in size the more distant they are from the head. The tapeworm is an hermaphrodite. It is provided on its head with four sucking discs, by means of which it is enabled to attach itself to the intestinal mucosa. It derives its nourishment by means of pores from the intestinal chyme. The older proglottides contain a large number of fructified eggs. The latter are off and on emptied into the intestinal canal and then appear in the dejecta.

The ovum contains an embryo which requires for its development an intermediary host. After reaching the stomach of the intermediary host the envelope of the ovum is dissolved by the gastric juice. The embryo is now set free and finds its way either by the lymphatics or by the blood-vessels to some place (usually the muscles) where it settles. Here it surrounds itself with a sac, which later on may become surrounded with a calcareous deposit. In this condition the embryo is called cysticercus or measle. 23

When the measle again reaches the stomach of a new host it then opens and its scolex advances into the small intestine, where it develops into a full-grown taenia.

Ascaris Mystax

A round-worm resembling ascaris lum-bricoides but much smaller and somewhat thinner. This parasite frequently occurs in animals, principally in cats, but has been discovered very rarely in man. No symptoms whatever have been observed.

Nematodes (Round Worms)

The round worms which occur as parasites have a slender, cylindrical, sometimes filiform body, with neither segments nor appendages. The integument is thick and elastic. The oral opening is at one extremity and provided with either soft or hornlike lips. The alimentary canal extends throughout the entire body cavity, terminating in an opening upon the ventral side at a short distance from the posterior extremity. The sexual organs and their orifices lie on the ventral surface. The female aperture is located at about the middle of the body; in the male the sexual orifice is situated close to the anus. The males are usually much smaller than the females.