184 THE GROUSE IN HEALTH AND IN DISEASE 



of the alimentary tract cause very definite and often very fatal 

 diseases, and to diminish this cause of death the parasites 

 must be eliminated or their access to the body of the bird 

 prevented. Consideration of the diseases thus set up will 

 come elsewhere, and here it should only be remarked that the 

 expression " the grouse-disease " is a misleading one. As if a 

 Grouse or any other living creature suffered from only one 

 disease ! What is usually meant by " the " disease is a some- 

 what sudden and very virulent disorder which sweeps through 

 a district and in a very short time carries off a very large per- 

 centage of birds. Such a disease was investigated by Dr Klein 

 some twenty years ago, and it is proposed that this disease 

 if it be a distinct disease be called Klein's Disease of the 

 Grouse. Since the Committee was appointed there seems 

 to have been no definite outbreak of Klein's disease, but 

 innumerable Grouse have been examined which were said by 

 the game-keepers and moor-owners to be affected with or killed 

 by " the " disease, which further investigation has shown to 

 have been done to death by worms or Protozoa. The symptoms 

 of " the " Grouse Disease are not readily apparent, especially 

 to the unclinical eye. 



ECTOPARASITES 

 INSECTS. 



A. MALLOPHAGA. Bird-lice or Biting-lice. 



I. Goniodes tetraonis, Denny. 

 The Broad Bird-louse of the Grouse. 



The bird-lice comprise a number of forms, sometimes also termed 

 biting-lice, which in the great majority of cases live on the skin of birds. 

 A few, such as the dog-louse, 1 live amongst the hairs of mammals. As 

 this is the alternate host of a common tape-worm, 2 which passes its 



1 Trichodectes latus, Nitzsch. 2 Dipylidium caninum (L.). 



