GROUSE DISEASE 193 



If we now turn from what must seem rather 

 negative criticism to the more positive results 

 attained by the investigation of the Departmental 

 Commission, we may begin by pointing out some 

 of the difficulties which confronted the Inquiry. 



In considering exceptions it is so immensely 

 important to know the rule. In studying dis- 

 ease our starting-point should be the normal, 

 the healthy ; yet until lately no one has studied 

 the healthy grouse, and indeed it is almost im- 

 possible to find a normal grouse, i.e., one free 

 from parasites. A grouse cannot express to 

 us its feelings ; the state of its tongue, the rate 

 of its pulse, even its temperature tell us nothing 

 because we have no norm and no means of esti- 

 mating the extent to which a diseased bird 

 has departed from the standards of a healthy 

 grouse. The nature of the numerous kinds of 

 blood corpuscles, which alter in proportion so 

 markedly in animals when they become parasi- 

 tized, was but a few months ago quite unknown, 

 the " blood count " uninvestigated ; in fact, 

 the Inquiry started, as regards the cause and 

 symptoms of the diseases which affect grouse, 

 practically at scratch. It was, of course, known 

 that the suffering birds lose their activity and are 



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