igo STUDIES IN INSECT LIFE, ETC. 



it at that. But grouse suffer and die from 

 many diseases. In a few dozen birds examined 

 chiefly in Cambridge the following disorders 

 were seen : Pleuro-pneumonia in a bird which 

 had lived long in captivity ; pericarditis ; necro- 

 tic changes in the liver ; chronic diseases of the 

 peritoneum ; and a septic infection due to gan- 

 grene supervening upon a broken wing. 



Sick and dying animals are apt to creep away 

 into corners and hide themselves, thus it comes 

 about that when these animals die patently 

 and in large numbers, the public is apt to regard 

 this mortality as due to some disorder peculiar 

 to the animal in question, and the disease re- 

 ceives the name of the species which is afflicted. 

 Hence we hear of such illnesses as " horse-sick- 

 ness/' " silk-worm disease/' and " grouse disease." 



The disorder which is usually associated 

 with the too comprehensive expression " grouse 

 disease " was investigated by Klein some 

 eighteen years ago, and in this article it will 

 be called Klein's grouse disease. Klein found 

 in the tissues of the bodies of birds that had 

 been dead for some time a certain bacterium, 

 whose nature and life history he investigated. 

 This bacterium is now recognised as one of 



