PHYSIOLOGY AND ANATOMY OF RED GROUSE 111 



Many such variations have come to light during the past five years in 

 the course of dissecting something like a couple of thousand Grouse : of these 

 some were healthy and some unhealthy ; but in this chapter no account is 

 given of lesions resulting from shot wounds or collision with wire fences or 

 similar accidents. This subject is dealt with in another chapter. 1 



By far the more important pathological changes which are to be found 

 in the Red Grouse are those which result from excessive parasitism, and 

 they are therefore discoverable as a rule in the intestines, and above 

 all in the two blind csecal appendices, which afford a habitat to 

 thousands of the round - worm Trichostrongylus pergracilis. The 

 particular csecal lesion, connected with this threadworm, and with 

 the fatal Grouse disorder which is now called Strongylosis, will be dealt with 

 separately. 2 



It will best serve the purpose in view to take again the alimentary tract 

 from end to end, and to mention the lesions to which the various parts are 

 liable. 3 



It is a very rare thing to find any disturbance in the upper reaches of 

 the alimentary canal. The mouth, the oesophagus, the crop, the proventriculus, 

 and the gizzard as a rule carry no entozoa, and are very seldom the seat of 

 any pathological trouble. But it may happen that a bird gets hold of some 

 irritant poison with its food, and this probably accounts for one or two other- 

 wise unaccountable cases of inflammation of the crop walls, with engorgement 

 and enlargement of all the vessels ramifying over it, and desquamation of the 

 lining membrane (e.g., Nos. 1611 and 1759). 



In one bird (No. 1703) the crop contained plenty of fresh green Calluna 

 tops, with Blaeberry leaves and bits of Potentilla, mixed up with abundant 

 legs of the crane fly, all perfectly normal and wholesome foods, 

 but the wall of the crop was excessively inflamed, the lining tfonof mi 

 membrane shed, and a roughened surface was left exposed ; there was ' rop ' 

 much fluid mucus, and all the vessels were injected and engorged. There was 

 also thickening of a granular appearance in the lower third of the oesophagus ; 

 but the mouth, throat, and trachea were all healthy. The mesenteric vessels 

 were engorged and varicose, and the bird, which was a cock, and a bad case 

 of Strongylosis, was infested with both kinds of tapeworm, weighed 15 ounces 

 only, and was found dead. 



1 Vide chap. ix. p. 153 et seq. - Vide chap. x. p. 207. ' J Vide Diagram, p. 290. 



