"GROUSE DISEASE" 161 



The last four years of the Committee's work were devoted 

 mainly to the study of the foregoing questions. The detailed 

 results of their investigations are given at length in the original 

 Report, and, though their conclusions may be subject to modifica- 

 tions in detail, it may be claimed that these have gone far to 

 elucidate the main points involved. These conclusions may be 

 summarised as follows : 



1. So far as the observations of the Committee were con- 



cerned Klein's infectious pneumonia is not a separate and 

 distinct disease from Cobbold's Strongylosis. In fact, 

 to be more precise, Klein's disease was never observed. 



2. The life history of the threadworm Trichostrongylus 



pergracilis was satisfactorily traced. 1 



3. The investigations failed to establish any connexion 



between " Grouse Disease " and bacterial infection due 

 to the presence of parasites or any other cause. 2 It 

 was not found that the bacilli which find their way into 

 the organs did much harm. Some harm no doubt they 

 do ; but how much cannot be accurately ascertained. 



4. It was not found that mortality was due to toxaemia 



caused by parasites in the intestine. 



5. It was not found that extreme mortality among adult 



Grouse was caused by the presence of parasitic protozoa 

 in the intestine. 3 It may, however, be noted that in 

 the course of investigating this point the Committee dis- 

 covered a hitherto unobserved disease among immature 

 Grouse, which was caused by the presence in large 

 numbers of the protozoal parasite Eimeria (Coccidium) 

 avium in the intestine. 4 



6. The ectozoa and entozoa of Grouse were carefully investi- 



gated, but no extensive mortality could be traced to 

 any of them with the exception of the Trichostrongylus 

 pergracilis of Cobbold, and to some small extent to the 

 smaller tapeworm Hymenolepis microps. 5 



1 See chap. viii. pp. 219 et seq. 2 See chap. viii. pp. 215 et seq. 



See chap, ix. p. 244, 4 Ibid. pp. 244 et seq. t 6 See chap. vii. p. 198> 



