Mr. Rainey on the Structure of the Cysticercus cellulosae. 491 



to separate them longitudinally ; however that may be, it is an 

 abnormal condition, and always coexistent with the higher 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 mole- 

 cules, which, so far as I am able to judge from the comparison of 

 such extremely 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 inappreciable, 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 ex- 

 cepting in conjunction with the earliest stages of the Cysticerci, I 

 am inclined 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. 6. — 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 ven- 

 tral portion of the perfect animalcule, with this difference only, 

 that these cells are compressed. The next change which is visible 

 is the formation of folds, which become more perceptible as the 

 animal increases in breadth, and which remain in the perfect 

 entozoon so long as it is confined to a small space, but dis- 

 appear 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 diseased 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 appears to be drawn inwards, 

 forming a hollow ; at the bottom of which, the granular material 

 is deposited from which the suckers, booklets, and calcareous 

 granules are formed, as above described. 



