Fig. 110.—Haplosporidium heterocirri. Section throughout wall of the Polychæte worm, Heterocirrus viridis, showing various developmental stages of the Haplosporidium. × 550. (After Caullery and Mesnil.)
Fig. 111.—Haplosporidian spores. a, b, Haplosporidium heterocirri. a, fresh; b, after immersion in sea water; c, d, Urosporidium fuliginosum. × 1000. (After Caullery and Mesnil.)
Rhinosporidium kinealyi, Minchin and Fantham, 1905.
Rhinosporidium kinealyi, parasitic in man, must now be considered in greater detail. This organism was found in nasal polypus in India, and has since been recorded from the ear as small nodules in the external auditory meatus. The Indian cases came from the neighbourhoods of Calcutta and Madras, and the parasite has been seen in Ceylon. Similar structures have since been described from the United States and South America.
The Rhinosporidium polypus is said not to be particularly painful, though nasal forms must interfere with breathing to some extent. The first nasal polyp reported from India formed a vascular pedunculated growth on the septum nasi and was about the size of a large pea or raspberry. It was compared with a raspberry, being red in colour with a number of small whitish dots upon its surface. When the tumour was cut, a number of similar whitish dots were seen within. These were the cysts of Rhinosporidium. According to Minchin and Fantham[240] (1905), they vary considerably in size and measure up to 200 µ or 250 µ in diameter. Each possesses a cyst wall which varies in thickness in different cysts. Its outer wall is always firm and distinct, the inner limit being less definite at times. Each large cyst is filled with numbers of spherical or oval bodies, showing every gradation between small ones at the periphery and large ones at the centre (fig. 112). Roughly, three zones of parasites can be distinguished in a large cyst, a peripheral set consisting of the youngest parasites, an intermediate group and a central, oldest zone. A large cyst may possess a pore for the egress of its contents. Some of the cysts show polar distribution of the zones.
The youngest forms of Rhinosporidium are difficult to detect. They are small, granular masses, round, ovoid or irregular and at times even amœboid in appearance. These are young trophozoites. They increase in size, but encystment occurs early, the outer layer becoming firm so that the organisms have a definite contour. Each is soon multinucleate and the cytoplasm segments around the nuclei. The cyst thus becomes full of uninucleate pansporoblasts or sporonts, with a peripheral layer of undifferentiated protoplasm. The pansporoblasts grow in size. In the larger cysts the formation of pansporoblasts progresses at the expense of the peripheral layer of protoplasm, which, however, continues to grow, so that the cyst as a whole increases in size. The pansporoblasts at first are uninucleate (fig. 112, a), and then undergo nuclear multiplication. This is well seen in the intermediate zone of parasites, where the pansporoblasts show first one, then two, then four or more spores (fig. 112, b), while in the oldest centrally placed pansporoblasts, about a dozen or sixteen closely packed spores (fig. 112, c), can be seen. The spore is small and rounded, and its nucleus is clear and distinct. The fully formed pansporoblast or spore morula becomes surrounded by a membrane.