PHYSIOLOGY AND ANATOMY OF RED GROUSE 121 



On the whole the mechanical view seems the most probable. The peristalsis 

 is acting in a way to dislodge the worm, and the Trichostrongylus has no other 

 way of retaining its position in the creca save by coiling round something, and 

 the peristaltic action of the caecum must be fairly strong in comparison with the 

 strength of the worm, for the free end of the worm has to be released at every 

 wave of peristalsis from immersion in a thick, pasty material which is being 

 driven outwards at each contraction of the gut. It thus seems evident that 

 the small and delicate processes of the villi may be continually on the stretch, 

 at first looped round tightly by a worm, the coil may then relax, blood may 

 enter the capillaries, only to be compressed anew and so on, conditions 

 which cannot but produce congestion on a large scale if multiplied a sufficient 

 number of times. 



So far as the appearance of the caecum in disease (Strongylosis) is con- 

 cerned, the following rough, laboratory notes describe some of the 



Examples 



types : — of strongj'. 



(No. 1908.) Found sick. The caecal mucosa not very red, but 

 whitish, pale, the caeca full of mucus, and innumerable Trichostrongylus. 

 Congestion apparent in the mesenteric vessels but no marked villous engorge- 

 ment, only mucus in excess. 



(No. 1875.) Trichostrongylus very abundant, but no excessive amount of 

 villous engorgement. Contents of cEeca almost nil, this may account for subsid- 

 ence of engorgement and reduction of redness. 



(No. 1854.) Caeca very badly engorged at lower open ends, but less 

 towards centre. The whole gut swollen, foul and unwholesome, and To-icho- 

 strongylus very abundant. 



(No. 1844.) Cjeca much swollen and very full of material. Excessive 

 villous congestion and redness. Abundant Trichostrongylus. A hard con- 

 cretion at the blind end of one caecum shows that matter may remain there 

 sometimes for lengthy periods. The whole venous system intensely con- 

 gested, and the swellings on the caecal ridges exceptionally red with engorged 

 villi. 



(No. 1842.) Caeca very much swollen, villous redness much marked, and 

 very deep in colour. The whole contents lumpy and irregular, soft and 

 hard, partly dried up, so that from without whitish lumps showed through. 



(No. 1839.) Cajca very large and unhealthy, thick with whitish mucus. Red 



