PHYSIOLOGY AND ANATOMY OF RED GROUSE 119 



gestion. There is also little doubt that an observer may be easily misled by 

 a physiological redness of the cascal villi due to normal processes of digestion. 

 This is especially the case if the bird examined happens to have been in the 

 middle of this process at the moment of death, and if death occurs without loss 

 of blood. The abdominal viscera must all be more full of blood at that time 

 than at others, though in a bird like the Grouse which eats all day long, the 

 difference may be less marked than it would be in ourselves or in birds of 

 prey which feed at longer intervals. 



The chief signs of a bad case of Strongylosis so far as the caecum gjg ns of 



OJ Strongy- 



is concerned are : losis - 



(1.) An excessive number of the worms, which can be seen stringing across 

 between the mucosa and the caked contents of the gut, if the contents are 

 fairly dry. If not, then, by taking a small quantity of the pultaceous 

 contents and squeezing this flat between two glass sides, the worms can be 

 easily seen as transparent threads when held up to the light. Innumerable 

 ova will also be found lying free in the caecal contents. 



(2.) The longitudinal ridges, eight to nine in number, are very much 

 thickened, chiefly because the amount of blood held by them is excessive, 

 and the villi are all engorged. 



(3.) The swellings shown in PI. xxx. (Fig. 1), and conspicuous in a 

 healthy bird as greyish nodules, are far more conspicuous in a case of 

 Strongylosis when they are reddened and congested, and seem to suffer to 

 a greater extent and earlier than the remainder of the ridges and the rest 

 of the caecum (see Plate xxx., Figs. 6 and 7). In some cases, however, 

 the time comes when every villus in the whole gut seems to be intensely 

 red and congested from one end to the other (see Figs. 8 and 9). 



(4.) There may be a very great deal of mucous thickening, from the swelling 

 up of the villi and their columnar epithelium cells, and after maceration post- 

 mortem, the cascal mucosa seen in water may have the appearance of a 

 furry rug. The mucous contents of such caeca are sometimes obviously 

 blood - stained, and there is probably a haemorrhagic form of the disease 

 which results from the sudden access to the gut of a very great number of 

 larval worms all in a fully metamorphosed state. Such a case was produced 

 experimentally at Frimley, and haemorrhages occurred in the caeca. There 

 is no apparent reason why under certain easily imagined circumstances the 

 same thing might not happen in early springtime under natural conditions. 



