Besides dysenteric amoebae which have been described above, a similar variety is occasionally encountered giving rise to no symptoms whatever or sometimes to slight attacks of diarrhoea.

1 Leuckart: "Die menschlichen Parasiten," Leipzig, 1886, Bd. ii.

Sporozoa

Among the sporozoa coccidia are occasionally found in the stools. This organism is egg-shaped, provided with a thin shell, 0.02 mm. long, and contains in its interior a large number of nuclei usually arranged in groups. The coccidia do not seem to have any pathological bearing.

Infusoria

To these belong cercomonas intestinalis, trichomonas intestinalis, and paramaecium coli. All of them are found principally in conditions in which diarrhoea is the foremost symptom.

The cercomonas intestinalis is pear-shaped, has a distinct nucleus and eight flagellae. The head portion of the body tapers obliquely and presents a depression (Fig. 39). It is not believed to have a direct pathogenic significance.

Cercomonas Intestinalis (Da vaine)

Fig. 39. - Cercomonas Intestinalis (Da-vaine).

Trichomonas Intestinalis (Zun ker)

Fig. 40. - Trichomonas Intestinalis (Zun-ker).

It is assumed, however, that this micro-organism is liable to prolong pre-existing catarrhal affections of the intestine. Trichomonas intestinalis presents the same features as the cercomonas and can be distinguished from the latter by its somewhat greater size and the row of fine cilia upon the periphery of its body (Fig. 40). In fresh dejecta this micro-organism moves around very actively. Zunker 1 found it principally in mushy dejecta having a brownish-yellow color and a somewhat putrid odor.

1 Zunker: Deutsche Zeitschr. f praktische Medicin, 1878, No. 1.

Paramcecium (or balantidium) coli is egg-shaped, 0.1 mm. long and covered with fine cilia, the latter being densely grouped about the mouth, while but few of them surround the anus. In the interior of this organism are found a nucleus and two contractible vesicles, besides fat droplets, starchy particles, etc. (Fig. 41). The balantidium coli was first described by Malmsten 1 in 1857. In the fresh stools the balantidium moves about very rapidly, but it dies as early as one-half an hour to two hours after the dejecta have been passed. Like the cercomonas, the paramaecium coli is believed to keep up conditions of diarrhoea.

Balantidium Coll (Claus). a. Mouth: b, nucleus; c, a granule of starch which has been ingested: d, a foreign body in the process of being expelled. Highly magnified.

Fig. 41. - Balantidium Coll (Claus). a. Mouth: b, nucleus; c, a granule of starch which has been ingested: d, a foreign body in the process of being expelled. Highly magnified.

The treatment directed against these infusoria consists in intestinal irrigation with watery solutions of tannic acid, boracic acid, thymol, or quinine.