566 SCIENCE PROGRESS 



prehensive expression "grouse disease" was investigated by 

 Klein some eighteen years ago, and in this lecture 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 the Bacillus coli group, 

 a widely spread group of bacteria which are found universally 

 in the alimentary tract and which rapidly invade the tissues 

 of the body after death. At the time Klein was working 

 bacteriology was comparatively a new subject, and this invasion 

 by bacteria of the tissues at the time of and after death was not 

 appreciated. 



Klein's grouse disease was associated also with some con- 

 gestion of the lungs ; the windpipe was described as dark in 

 colour, the air-sacs contained blood, in the cavities of the lungs 

 blood or some granular exudation occurred, the liver and 

 kidneys were congested and soft, and there was an exudation on 

 the peritoneum. We now, however, know that many, if not all, 

 of these appearances in the chief organs of the body are but 

 normal post-mortem changes and occur sooner or later after 

 death in birds which were perfectly healthy when killed. 

 Another feature attributed to the Klein's grouse disease was 

 that its onset was comparatively sudden, its course rapid, and 

 according to all observers it attacked healthy and plump birds. 

 The present Inquiry has not yet succeeded in coming across 

 any sick or dead birds which are plump or in good condition. 

 All the grouse, and they amount in number to nearly two 

 thousand, which have been investigated, have been weighed, 

 and in every case where there has been any disease there has 

 invariably been wasting ; the sick birds are always thin, have 

 lost flesh, and are in a poor condition. One final feature of 

 Klein's grouse disease is its seasonal incidence ; usually it is 

 said to occur with greatest virulence in the spring, to die down 

 during the summer, and to recur in a less virulent form in the 

 autumn. To this seasonal variation I shall return. 



Klein's grouse disease is still a matter of inquiry. During 

 the last five years, whilst the Commission has been prosecuting 

 its inquiries, this " disease " has frequently been reported, but 

 on investigation the characteristics enumerated above have not 

 been present ; still, the sportsman and the gamekeeper, who do 

 not weigh their grouse and seldom their evidence, and who are 



