TRICHINA SPIRALIS. 343 



according to its movements, is longer or shorter, sometimes straight, 

 sometimes undulated, thicker or thinner, and marked by two 

 dark lateral outlines; this is the narrow commencement of the 

 alimentary canal. This is followed by a canal which constantly 

 increases in width posteriorly, with a simultaneous gradual 

 enlargement of the Trichina ; this occupies the anterior two 

 thirds of the worm, and sometimes reaches nearly to the lateral 

 margins of the worm, but is sometimes further removed from 

 them, so that a vacant space occurs between the lateral margins 

 of the worm and the margins of the nearly spiral intestinal tube, 

 which at first forms undulatory curves nearly touching each 

 other, and in their further course form a series of constrictive sac- 

 like dilatations, which are probably capable of enlargement and 

 contraction. Besides this, transverse stria? run across the worm, 

 which give it the appearance of consisting of ring-like joints 

 pushed one into the other. 1 The contents of the intestine 

 consist of finer and coarser elementary granules, often with the 

 outlines of the roundish or elliptical bodies contained in the 

 cyst. At the passage of the second into the last and thickest 

 third of the body, the intestine, which has hitherto presented a 

 moniliform appearance, forms a pyriform or infundibulate figure 

 with smooth outer walls, which presents a very short narrow 

 neck, followed by an intestine which is again enlarged to a 

 certain degree, and runs, without dilatations, in a slightly un- 

 dulatory course, through the end of the abdomen nearly to its 

 extreme obtuse apex. The contents of this portion of the in- 

 testine are paler than those of the upper tube ; larger elementary 

 corpuscles with dark outlines are perceived, and in the living 



1 The clear round points, which, according to Luschka, lie under every transverse 

 line, but the import of which he could not discover in any way, do not in reality exist, 

 but are optical appearances, which probably depend upon the circumstance that the 

 contents of the intestinal canal, which are tolerably clear in themselves, are thinnest in 

 the middle of the intestine behind the constrictions, as this very point in each con- 

 stricted portion of the intestine forms the highest, and foremost point, but the contents 

 undoubtedly pass more backwards and towards the dilatations. If the intestine of a 

 Trichina were as full as it could hold, the light would be deficient, as also if the con- 

 tents were dark-coloured throughout, as is the case, for example, in subsequent stages of 

 existence with the Trichocephati which live upon the dark-coloured paste of the intes- 

 tines. These points may also perhaps be owing to the convolutions of the intestine, 

 which at first are very close together, leaving, nevertheless, small vacuities where the 

 convolutions do not cpuite touch each other. The parenchyma shining through these 

 vacancies forms the light points. 



