90 Maddox, on Parasites oj the Common Haddock. 
I should regard the cyst as passive, not endowed with growth 
or conversion of material , but sufficiently porous to admit 
pabulum through its surfaces ; and it seems probable the 
creature is also capable of reabsorbing this deposited matter, 
as in the case of the removal of the walls of closely adjoining 
cysts, figure 6 , which, we could hardly expect without some 
trace, if the cysts contained an external tunic of the fibrous 
and elastic tissues of the infested animal. Although the 
larger number of these cysts is placed in the very structure 
of the nerve, the component fibres and vessels, &c., seem to 
be uninjured, the expansion and growth of the parasite 
appear to have been most gradual. I could find no change 
pathologically, nor can we say if there had been any effect 
in the physiological relations of the surrounding parts. I 
saw no wasting of the structures, and the only difference 
noticed was in some of the neighbouring muscles ; they 
appeared here and there to be somewhat discoloured, yellower 
than the rest, a fine granular substance investing the fibres 
and fasciculi, though the intimate structure was quite as 
perfect as in the normal tissue. I cannot say whether any 
portion of the interior of the cyst should be regarded as the 
remains of ecdysis. In some, loose particles are found, which 
may be excreta. 
On rupturing the largest of the cysts, containing the 
entozoon alive, with the dissecting needles, a small quantity 
of viscid fluid with variable sized oily-looking globules 
escapes, and with it the parasite ; almost immediately if this 
be done in water or any saline liquid, or weak glycerine, I 
have noticed the creatures retain much of the form in which 
they emerged, andremain more or less permanently contracted: 
but in warm saliva, for the intimation of wdiich I am indebted 
to my friend Professor Aitken, the animal often moves some- 
what freely about with a slow graceful motion, and the 
internal textures are very much less obscured than in other 
media, which do not render them too transparent for distinc- 
tion. I have watched one specimen alive in this medium for 
seven hours, how much longer it remained living I can’t say, as 
I left it to retire for the night, but the next morning at eight 
o’clock there were no signs of life. The general aspect of the 
creature is elongated, roundish, rather narrower posteriorly 
and somewhat leech-like, about 7^0^ to iVe-th of an inch in 
length, the entire surface of the body covered with minute 
spines set backwards, but more particularly, as pointed out by 
Mr. Goodsir, evident on the entire dorsal aspect. It is pro- 
vided with an anterior or oval disc, and a central one situated 
about the junction of the first and second third of the body. 
