324 PROCEEDINGS OF SECTION D. 



to detect some movement of the adult female, especially manifested 

 by a tendency for the cut ends to protrude very slightly but de- 

 finitely from the tunnels. In such very fresh nodules a considerable 

 length of worm may be withdrawn by gentle traction, showing that 

 it lies practically free within the tunnels, and, moreover, possesses 

 some freedom of movement while enclosed within the nodule. 



Microscopical Appearance of Nodules. (See figs. 1, 2, 30, 31, 

 32) — Sections made serially of different sized nodules showed the 

 general structure to be the same in each instance. The capsule is 

 composed of dense fibrous tissue with many nuclei, and processes 

 therefrom pass inwards, branching and anastomosing to form the 

 walls of the spaces or tunnels within which the adult parasite lies, thus 

 forming what we have termed the worm-area. In the very smallest 

 nodules the fibrous capsule is often very thin, while the branches 

 entering the worm area are extremely delicate. A very notable 

 feature of the " capsule," especially in the larger tumours, is the 

 extraordinary thickness of the walls of the arteries compared with 

 the very small size of the lumina. This thickening is due to a 

 peri-arteritis, and is often accompanied by a definite end-arteritis, 

 and not infrequently an obliteration of the lumen. In certain 

 nodules a section of the wall seems to be chiefly composed here and 

 there of arteries with greatly thickened walls, between which there 

 is a comparatively loose new connective tissue with many newly- 

 formed blood vessels. 



In the thinner capsules, particularly those of very small in- 

 fertile worm nodules, the thickening of the arterial walls, unless at 

 the point of entry, is not marked. Further, in those nodules com- 

 posed of much fibrous tissue numerous larvae can be seen traversing 

 the tissue and often congregated in the vicinity of the blood vessels, 

 whereas in those with very thin capsules migrating larvae are seldom 

 if ever seen. 



The fibrous bands forming the walls of the tunnel vary very 

 much in thickness and in density ; frequently they are only repre- 

 sented by a few delicate strands ; at other times, especially towards 

 the surface of the worm area, the breadth of these bands exceeds 

 the diameter of the tunnels. 



In the deeper portions of the worm-area, especially around the 

 heads of the parasites, the tissue is much looser in character, the 

 nuclei are more numerous, and there is generally greater or less 

 infiltration by leucocytes, and especially eosinophiles, which are 

 often massed at the edge of the tunnel wall. The leucocytes are 

 undergoing degeneration in certain areas, as shown by the nuclear 

 disintegration and indefinite staining reaction. 



Structure of the Parasite. 



As stated previously, the worm lies closely coiled in a very 

 complicated manner in the interior of the nodule, usually, but not 

 necessarily, situated centrally. At times the matrix immediately 



