Cause may 

 be thread- 

 worms or 

 tape- 

 worms, 



PHYSIOLOGY AND ANATOMY OF EED GROUSE 113 



oesophagus, and thus paralysing this part of the alimentary tract by over-distension. 

 The contents were not examined for irritant poison, but the birds might possibly 

 obtain some such poison if they fed off heather which had been contaminated 

 by sheep dip in dry weather. This, however, is not probable in March. 



In the duodenum it is comparatively common to- find the mucosa intensely 

 engorged, showing a bright red surface to the naked eye, sometimes all over, 

 and at other times in patches. This is apparently the result some- 

 times of the presence of Hymenolepis microps, in large numbers ; ment in 

 sometimes of the presence of Trichosoma longicolle. Such a mucosa, 

 seen under the lower powers of the microscope, shows that the vessels of 

 the villi are all full of blood as shown in the accompanying figures (see PI. 

 xxviil., Figs. 4 and 4 (a)); but although in many cases the mucosa is 



thus reddened and Hymenolepis and Trichosoma are abundant, it is be thread- 

 won" * 



also quite as frequently found that the worms are present without tape 

 any reddening, and in some cases reddening is present without any 

 sign of a worm. Nevertheless one very common association in the duodenum, 

 whether it has anything to do with cause and effect or not, is that in one and 

 the same bird Hymenolepis occurs in very large numbers, the villi are densely 

 injected, and the fluid bathing the worms has the appearance of being bloody 

 (see PI. XXVIIL, Fig. 2). 



For example, in No. 1200, weighing 21^- ounces, found sick, the duodenum was 

 of a deep red both inside and out, the villi all injected, the mesenteric vessels 

 all engorged, and Hymenolepis was present. The bird had, however, Or corn 

 been feeding on corn, and it is possible either that the siliceous feedm g- 

 spicules of the oats were the cause of much irritation, or that the general 

 venous engorgement resulted from the Strongylosis which was also present. 



It is also probable that in many of these cases where there is villous 

 engorgement and redness of the mucosa in the duodenum and smaller intestine, 

 Coccidia have been the cause and have been overlooked, and that Or 

 the more obvious threadworms (Trichosoma) have really little or Coccldia - 

 nothing to do with the engorgement. 



It may exonerate Hymenolepis and Davainea to some extent, that both 

 may be present in masses without any accompanying congestion, but the 

 occurrence of a large number of Trichosoma longicolle in the duodenum, 

 associated with an accompanying congestion of the mucosa, and the presence 



in the gut of dark bloody - looking fluid is too frequent to allow this 

 VOL. i. H 



