"GKOUSE DISEASE" 201 



the lung upon which Klein had relied in making a diagnosis of acute infectious 

 pneumonia differed in no way from the appearances which had been ^,!acter 

 observed by the Committee in the lungs of hundreds of birds found jstics found 



in all dead 



dead from all causes, including Cobbold's Strongylosis, general birds - 

 Helminthiasis, accidents, or even shot wounds. 



Klein describes accurately the post-mortem changes leading to a discoloration 

 of the lungs which invariably take place. These begin, almost always, where 

 the lung is in contact with the liver, and strongly suggest (what at first the 

 Committee frequently mistook it for) congestion and pneumonia. 



This discovery undermined the faith which the Committee were prepared 

 to place in the existence of Klein's acute infectious pneumonia, and it soon 

 became evident that in birds obviously dying of " Grouse Disease," there was 

 no dangerous ante - mortem infection of the lung or other tissues with the 

 bacillus in question, and no recognisable lesion in any organ of the bird except 

 in parts of the intestine. All the appearance of congestion and pneumonia in 

 the lung, the " inky " or " tarry" appearance of the liver, the small dark spleen 

 and the several other characteristics which were previously attributed to Klein's 

 pneumonic disease, were now found to be due to post-mortem change alike 

 evident in diseased and in perfectly healthy normal birds. 



The point was further tested by taking a number of healthy pigeons, and 

 killing the whole of them at the same time with chloroform. The 

 birds were numbered and opened on consecutive days and the change ment 

 in the appearance of the viscera was noted. It was evident that in healthy 

 every case where there had been extravasation of blood or serous fluid 

 owing to rough handling, or damage by the knife in dissecting the pigeon, the 

 tissues of the lung became black, and took upon themselves precisely the same 

 appearance that is seen in a Grouse found dead upon the moor, or examined 

 some days after being shot. The appearance of pneumonia was evidently due 

 to a soaking of the lung-tissue in decomposing blood and serum, and the post- 

 mortem colonisation of the tissues by Bacillus coli. 1 



Once this fact became clear, the Committee was no longer burdened with 

 the task of recognising and investigating the type of " Grouse Disease " 



described by Professor Klein, for it now became impossible to accept his be investi- 

 gated by 



explanation of the disease. This being recognisedit became necessary to set the Com- 

 on foot more detailed investigations to determine the following points : 



1 Vide also chap. xii. pp. 273 et seq. 



