302 THE GROUSE IN HEALTH AND IN DISEASE 



injures the mucous membrane of the cseca, and that this injury allows of the 

 Conolu- absorption of certain intestinal micro-organisms into the portal blood, 

 sions. j doubtless allows also of the absorption of other substances of an 

 irritating or poisonous nature, and probably interferes with the normal 

 selective absorption of nourishment. If we are right in thinking that the 

 csecal contents become partly retained, and stick to the absorbing surfaces of 

 the ridges of the mucous membrane, we have still more reason to believe 

 that nutrition is greatly interfered with. 



" Grouse Disease," as we see it, appears to us not to be a specific bacterial 

 infection. We conceive that all the birds which are more or less severely 

 aifected by Strongyli suffer injury from this cause to an extent which is 

 more or less proportional to the severity of the infection. Some exceptionally 

 strong birds may stand a larger infection better than weaker birds will 

 stand a lesser; but, on the whole, the birds with the largest numbers of 

 Strongyli suffer most. Their nutrition is impaired owing to interference 

 with the normal absorption of digested food, and to the abnormal absorption 

 of soluble poisons and intestinal bacteria. Such birds become the weakest ; 

 and when food becomes scarce, as it does at the beginning of spring, especially 

 after bad winters or on overstocked moors, or when other harmful influences 

 prevail, it is the weakest birds which suffer most. They die of privation 

 acting on a constitution already weakened by the consequences of Strongylosis, 

 while their stronger neighbours manage to pick up a living somehow, and 

 tide over the period of distress. 



