348 ANIMAL PAEASITES. 



crushing the worm. This latter fact can certainly not be denied, 

 but nevertheless I do not believe in a free suspension of the 

 internal parts within the membranous cylinder which is formed 

 by the external envelope of the worm. On the contrary, I 

 believe that there is always an extremely delicate, elastic, 

 structureless parenchyma between the walls of the intestine and 

 the envelope of the body, which yields and allows itself to be 

 displaced, dislocated, or compressed on the lightest pressure, and 

 only becomes converted into a more highly organized and more 

 resistent parenchyma, which may be recognised as composed of 

 muscular fibres, during the subsequent development of the 

 animal. One proof of the existence of a tissue of this kind is 

 afforded by the two dark, but very fine lines, recognisable in every 

 position of the animal, running from the head to the caudal ex- 

 tremity ; even according to Luschka, these indicate the existence 

 of contractile fibres, which have to do with the abbreviation and 

 elongation of the animal, and, as has already been stated under 

 the Trichocephali, they are the optical expression for the boundary 

 lines to which the parenchyma extends within the membranous 

 cylinder. 



Further destination of the Trichinae. 



There is no doubt that a great number of the Trichinae, if not 

 all those specimens which occur in the muscles of man, become 

 abortive and die. The latter then lie in their cysts in the midst 

 of the cyst-fluid, which is in course of sebacification, desiccation, 

 and calcification, rolled in spiral convolutions, in the same way as 

 the Trichina met with in a living state. These spiral struc- 

 tures are broken up into a number of fragments, which partly 

 lie loosely together, partly still have some connection, and, as 

 Luschka further states, are marked in their separation by dark 

 transverse lines. This arrangement, as also the ringed appear- 

 ance of the fragments, which resemble minute portions of glass, 

 weighs with me as a further proof of an indication of the seg- 

 mentation of the body of Trichina, which, in breaking up, 

 separates in the direction of the rings and in particular places of 

 this kind. Acids and alkalies have no action upon these remains, 

 the intestines of which at all events have undergone fatty 

 degeneration and passed over into the mass surrounding the 

 worm, together with which they then pass through further 

 changes which go on in it. 



