MYXIDIUM LIEBEEKUHNI 27 



in the urinary bladder of nearly all pike. It should be sought only 

 in freshly killed fish, as in a dead host it soon perishes. 



For the study of the living organism, the whole of the small 

 urinary bladder, which, in the pike, lies on the dorsal side of the 

 terminal portion of the intestinal canal, should be removed and opened 

 and its contents examined in the fresh state. Hairs or glass threads 

 should be introduced under the cover-glass to prevent the Myxides 

 from being harmed by pressure. The organisms are seen to be very 

 slow in their movements ; their shape, which changes, may be said 

 to be ribbon-like ; there is marked differentiation of the endo- from 

 the ectosarc. The hyaline ectosarc is particularly well developed in 

 parasites which live free in the lumen of the bladder ; in those which 

 are attached to the walls of the organ it is less clearly defined. The 

 endoplasm is surrounded by a layer of material, sharply separated 

 from it and finely granulated. The principal mass of protoplasm 

 is coarsely granular and rich in varied contents (spores, yellow 

 granulations, oil globules, and haematoidin crystals). 



The superficial layer surrounding the endoplasm may be seen with 

 great distinctness if a drop of weak watery solution of eosin be 

 introduced under the edge of the cover-glass. The superficial layer 

 becomes a light rose-pink and is easily distinguished both from the 

 uncoloured ectoplasm and the comparatively deeply stained endoplasm. 



The cnidospores are long in shape with a nematocyst at either 

 end. Two are formed within each pansporoblast, and they are always 

 found in pairs. They vary very much in numbers. It is probable 

 that during the winter months Myxides do not form spores at all. 



Cover-glass preparations of urine containing Myxides are useful 

 for observing cnidospores. They should be stained with iron-hsema- 

 toxylin. The method is not practicable for the preservation of the 

 whole organism, however, the Myxides being easily broken and 

 crushed in manipulating the thin smear. For this purpose, sections 

 should be made as follows : The whole of the infected bladder should 

 be removed and emptied of urine through the artificial orifice, It 

 should be filled with a fixing fluid by means of a pipette, and then 

 immersed in the same fluid in a shallow dish. Alcoholic solution of 

 mercuric chloride and Flemming's mixture are the best for this 

 purpose. The sections show Myxides in large numbers upon the 

 epithelial surfaces. Of these, some are furnished with a tapering 

 front portion, by means of which they are attached to hypertrophied 

 cells ; in others, this frontal portion is broadened out into a sort of 

 solelike attachment, by means of which they remain upon the 

 epithelial surface. 



