104 Helicosporidium parasiticum 
part of the filament takes the stain, while the peripheral refractive non¬ 
staining sheath either contracts or becomes invisible in refractive mounting 
Text-fig. 3. Different forms of unrolling spiral filaments without sporocyst; such forms 
are often found in fixed and stained smears. 
Text-fig. 4. Unrolled filaments in fixed and stained smears showing their nuclei. 
media. In iron-haematoxylin the filaments stain very slowly, but once stained, 
they are very retentive of the dark colour and are decolorised with difficulty. 
