disease 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 be- 

 cause 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 pro- 

 portion so markedly in animals when they 

 become parasitized, was but a few months ago 

 quite unknown, the " blood-count " uninvesti- 

 gated ; 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 more easily caught than 

 healthy grouse ; their flight is slow and limited 

 in length ; they are said to seek water ; the 

 " call " becomes feeble and hoarse ; the 

 feathers of the back and throat lose their lustre 

 and become ruffled ; the eye is dimmed. 

 But these external symptoms may be asso- 

 ciated with several diseases and diagnostic of 

 none. Nearly all of them occur in the two 

 diseases which, according to the Inquiry, are 

 responsible for a large percentage of deaths 

 among grouse. 



Each of these diseases is caused by an animal 

 parasite, and the investigation of the parasites 

 attracted the attention of the scientific members 

 of the Inquiry from an early date. 



Five years ago we knew two internal parasites 

 of the grouse (endoparasites) and two or three 

 parasites which live outside the skin (ectopara- 



