"GROUSE DISEASE "—PATHOLOGY 277 



post-mortem changes. We had the opportunity of seeing many of these 

 birds, for Dr E. A. Wilson, the Committee's field observer, was working at 

 Beaufort at the same time as ourselves, and it was he who first showed to 

 us the entozoal and other parasites of the Grouse. He, too, it was presence of 

 who first pointed out to us that the most notable lesions were in a^d'other 

 the cpeca. The mucous membrane often appeared deeply reddened P'^i'^^'tes. 

 along the convexities of the longitudinal ridges, and sometimes thickened. 

 To the naked eye, or with the aid of a hand lens, it was plain that con- 

 siderable pathological change had taken place here, but there was no obvious 

 ulceration. There were alwaj^s large numbers of Strongyli in these ceeca. 

 This condition was most advanced in birds which were picked up dead, but 

 it was no post-mortem change, for it was found also in weakly birds which 

 were brought to us alive. There were in these birds also many large tape- 

 worms, Davainea urogalli, in the intestine, fragments of which were found, 

 though rarely, in the cteca also. In the birds examined during the spring 

 there were invariably enormous numbers of the slender tapeworm, Hymenolepis 

 microps, in the duodenum, and the mucous membrane of this part of the 

 intestine was reddened. 



It was therefore necessary to carefully compare normal and diseased birds 

 (a) as to numbers of Strongyli ; (b) as to liability to contain living bacilli in 

 their organs ; (c) to make a detailed examination of the lesions in the csecal 

 mucous membrane, and to see what relation this had to the nematodes on 

 the one hand, and the bacilli on the other ; and lastly {d) to find out w^hether 

 or not, the bacilli exerted any pathogenic action. It seemed possible that the 

 Strongyli might be the cause of the changes in the csecal mucous membrane ; 

 that these changes might admit the intestinal bacteria to the liver and other 

 organs of the body, and that these together with other pathogenic products 

 abnormally absorbed from the diseased caeca, or possibly the mere interference 

 with absorption caused by that disease, might lead to the death of the 

 birds. 



All the diseased birds examined were considerably under weight and 

 wasted. We never came across any instance of a bird dying jj^ diseased 

 plump and in good condition, unless indeed its death could clearly i^^'ood^*"** 

 be attributed to some other cause, such as accident. condition. 



It was recognised from the first that, if micro-organisms were present in 

 the organs in small numbers only, somewhat large amounts of tissue might 



