330 THE GROUSE IN HEALTH AND IN DISEASE 



Third Theory : Kleins Disease. The third theory, asso- 

 ciated with what is commonly called Klein's disease, is that the 

 mortality can assume two forms, the first or epidemic form 

 (pneumo-enteritis), which sweeps the moor, and in which the 

 birds are said to die in plump condition, fully feathered ; the 

 other a lingering disease in which birds waste away and die 

 only after loss of plumage and weight. The Committee have 

 paid very close attention to Klein's disease, and the remarks 

 on p. 153 should be read. It may be noted that in all the out- 

 breaks investigated not one single case was found of birds 

 dying in good condition, i.e., at normal weight. On seventeen 

 different occasions during the course of the Committee's investi- 

 gations keepers have reported birds dying plump and fully 

 feathered ; in every case the spring balance has indicated that 

 the birds referred to were below the normal weight, and visceral 

 examination has shown that the caeca were charged with 

 Strongyle worms. 



Fourth Theory. The fourth theory put forward is that 

 when birds die of disease on lightly-stocked moors it is impossible 

 that they should die of shortage of food or by parasitic infection, 

 and that therefore midges or gnats must be the cause of death. 

 This theory is not supported by any ascertainable facts or data, 

 and, as far as examination of the blood goes, there is strangely 

 little evidence in its favour. 



It cannot be admitted that a shortage of stock on a moor 

 is necessarily a guarantee of immunity from infection by the 

 Strongyle worm, although it may lessen the risk of such infection. 

 It will be shown later that moors in Yorkshire, which one hundred 

 years ago were unable to carry three hundred brace to ten 

 thousand acres without a certainty of disease, have by careful 

 burning been made to carry ten times that stock without risk. 



Infection of a light stock can be brought about in various 

 ways : 



(1) If, in a hard winter, the birds are driven by snow off 

 their own ground and congested on a small feeding-area for a 



