THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 289 
attached firmly to Distoma foliwm (frequently found in the pike’s blad- | 
der); also attached to other myxosporidia. Observed by Biitschli in 
December. 
All individuals of Zuwcius from the Rhine and Saar have myxospo- 
ridia in the bladder, while those from the E]be and Weser territory only 
exceptionally show them (Pfeiffer, 1891, p. 110). 
Perrier erroneously cites the habitat as the air bladder. 
Pathology (Pfeitter)—The coarser anatomical details can be seen 
(under 300 or 400 diameters) by carefully stretching a bladder tightly 
over a cork, placing a cover glass underneath, brief fixation, and hard- 
ening by alcohol and staining. Control experiments may be made by 
maceration in diluted acetic acid. The infection of the bladder was 
also followed by capillary cultures. 
Mucous membrane, when slightly affected, showing individual clusters 
of 4, 5, 100 or more epithelial cells infected with myxosporidia; thence 
all grades of hypertrophy (up to 10 to 30 times the normal size) can be 
traced. 
Hypertrophy of epithelial cells:. When slight, the cells are swollen, 
shining, apparently lobed. Pfeiffer failed to differentiate the nucleus 
and the intruder, probably owing to early succumbing of the nucleus. 
With greater hypertrophy the cells are filled with and overdistended 
by the parasites; subsequently, continued growth of the my xosporidium 
ruptures the cell membrane; the myxosporidium flows amceboidly out in 
grotesque shapes, and immediately differentiates its hyaline ectoplasm; 
rupture of cell membrane visible under the microscope. Hematoxylin 
or phloxinred-methylenblue stains a narrow-bordered, dark globule in 
the interior of the swollen epithelial cells; nucleus of latter invisible; 
largest cells indicating, by ragged coloring of contour, the degeneration 
of the epithelial remains. 
Hffects (of this species??).—Of late years dead pike and perch have 
frequently floated down the Mosel and the Rhine. It is doubtful’ 
whether the disease here is the same as the muscle infection of the 
barbel. According to a statement [unpublished, I infer] by Dr. T. W. 
Miiller in Greifswald, the spore found in the flesh of the pike is not the 
same as that of the barbel, but is formed upon the type of M. lieber- 
kithnit (Pfeiffer). 
Whether the pike and per chi in the Mosel die from myxosporidiosis is 
unknown. With the perch, fungous disease concurs (Ludwig).? 
101. Myxidium ? ? incurvatum Thélohan, 1892. 
Compt. Rend. Acad. Sci. Paris, cxv, pp. 1093-1094. 
Cyst, probably none. 
Myxosporidium.—Small, feebly motile. Ectoplasm (in sections) very | 
clearly striate. me ndane the lobed, sometimes f>rming a bristly, shaggy | | 
coat, as in Myxidium lieberkiihnit. 
‘Die Protozoen als Krankheitserreger, 1892, 2 ed., p. 105. 
? Jahresber. d. rhein. Fisch.-Vereins Bonn, 1888, pp. 27, 28. 
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