STRUCTURE OF THE CYST1CERCUS CELLULOSE. 99 
forms of the Cysticercus ; and as the entozoon, as I have first 
described it, could not possibly have taken on that form all 
at once, these groups of molecules must therefore be looked 
upon as its antecedent stage, or as portions of Cysticerci in 
progress of development. But I also find in the specimens 
of muscle infested with these entozoa, many of the capillaries 
and smaller blood-vessels filled with organic molecules, which, 
so far as I am able to judge from the comparison of such ex- 
tremely minute bodies, seem to resemble those molecules 
which are found in the primary fasciculi. The vessels filled 
with these molecules have their coats so thin as to be in- 
appreciable, and some of the capillaries appear to be partially 
destroyed, and their molecular contents diffused among the 
sarcous elements. As this is an abnormal condition of the 
contents of these vessels, as well as of their coats, and, so 
far as my experience goes, is not found excepting in con- 
junction with the earliest stages of the Cysticerci , I am in- 
clined to believe that the molecules in question are the same 
as those in the primary fasciculi, and that it is by their 
coalescence in these fasciculi that the formation-cells of the 
Cysticerci are formed. 
Addendum , Dec. 6th. — After an entozoon has left the interior 
of a primary fasciculus, and arrived at the space between the 
muscular fibres, it loses its ciliated investment, and increases 
in breadth. Its margin now seems to be formed entirely by 
the convexities of the globular masses of cells of which its 
body appears to be made up, causing it to present a crenate 
form similar to that of the ventral portion of the perfect 
animalcule, with this difference only, that these cells are com- 
pressed. The next change which is visible is the formation 
of folds, which become more perceptible as the animal in- 
creases in breadth, and which remain in the perfect entozoon 
so long as it is confined to a small space, but disappear when 
it gets to the space between the surface of a muscle and the 
fascia covering it. The unfolding in this last situation seems 
to be produced by the imbibition of fluid, and the consequent 
distension of the ventral part. These more advanced stages 
of the worm-form are best found in those specimens of dis- 
eased muscle in which the perfectly developed Cysticerci 
abound. Their number in proportion to that of the perfect 
animalcules varies considerably in different specimens. 
I have always succeeded in finding some of those of the 
worm-form along with the perfectly developed ones ; and in 
some cases there are as many of one kind as the other. After 
they have acquired a certain breadth — about one twelfth, or 
the one eighth of an inch, — the central part of the cyst ap- 
