A PARASITIC DISEASE IN THE SMOKED HADDOCK 
Migration of the Central Protoplasmic Masses 
We observed a very curious appearance, depicted in Figs. 6 and 7, in nearly all 
our sections. This consists in the protrusion of the cyst wall by the parasite. A long- 
neck is formed to the cyst, rupture ot the thinned extremity takes place, and the 
contained protoplasmic mass, which has now assumed an elongated form, migrates into 
the surrounding necrotic material or into the adjacent muscle fibres. In Fig. 7 (3) a 
parasite is shown in the muscle fibre which has wandered out from its capsule. In 
Fig. 6, the winding nature of the path along which the parasite has travelled to reach 
the muscle is also clearly indicated. The paths along which the parasites wander 
after they leave their capsules, appear to lie in the intermuscular connective tissue, and 
they then either may penetrate into the muscle fibre, where they become encysted and 
produce a localized bulging of the fibre, or they remain in the intermuscular connective 
tissue. In nearly all sections traces ot the tree parasites as elongated or tapering 
protoplasmic bodies may be seen, and corresponding to this there are always a large 
number of empty capsules. 
Spore Formation 
We have not seen in any ot our sections any structure which suggests spore 
formation, nor, in tact, any definite segmentation ot the protoplasm. Here and there 
in the necrotic material, and also between the muscle fibres adjacent to the spindle- 
shaped mass could be seen small oval thin-walled vesicular bodies apparently devoid 
ot contents, which varied in size, and though resembling a cyst in nature had not the 
appearance ot spores. Further, in some ot the cavities usually occupied by the parasite 
are found instead spherical amorphous bodies. 
Nature of Parasite 
The naked eye appearance ot the spindle masses in the muscle suggested the 
idea that we had to do either with an encysted form ot a worm belonging to the 
Nemathehninthes., or with a parasite of a myxosporidian or sarcosporidian nature. In 
favour ot the former view is the fact that Professor E. A. Minchin, who kindly 
examined some ot our slides, is ot the opinion that the structures in question are really 
degenerated worms probably ot the order Acanthocephala^ and that some ot the masses 
described by us are really ova. We do not think, however, that this view can hold 
good, tor the whole structure has no definite outline as this would imply, but is, in 
tact, an ill-defined infiltrating mass, and the encysted bodies vary so much in size, 
that they can hardly be ova. There are equal difficulties in the way of accepting a 
neo-sporidian explanation. They appear to be structures totally unlike those hitherto 
described in these orders. They have no appearance ot spore formation, and the 
presence of a complicated structure, such as that of the radiate body ot Fig. 8, appears 
incompatible with bodies or a sporozoan nature. We must, therefore, examine it 
possible tresh material in tresh fish before we can hope to explain their nature. 
