"GROUSE DISEASE" 189 



was no rupture of the capillaries, and consequently no extravasation in the 

 cajca or in any part of the intestinal canal. That this congested state of the 

 villi was due to the strongyles appeared the more certain, since the turgidity 

 was only marked in that part of the cajcum where the strongyles were crowded 

 together." ' 



Dr Cobbold considered that the diliercnce observed in the intensity of the 

 disease during various epidemics might be partly accounted for by the presence 

 of tapeworms and threadworms in varying proportions in the same Grouse, but 

 that the strongyles were " sufficient by themselves to cause the death of the 

 host" without the "assistance of a second kind of parasite." - 



Klein too recognised, not so much a different type of disease in diflferent 

 years, as two distinct phases of the same disease in the same epidemic, namely, 

 that which is so acute as to kill birds in good condition without giving them 

 time to lose flesh, and that which is so much less acute that it gives its victims 

 abundant time to become emaciated before death. 



Cobbold, however, differed from Klein in one important respect, viz. : — that 

 he distinctly indicates that he did not observe any example of a Grouse dying in 

 good condition and without loss of flesh. 



Neither Klein nor Cobbold suggest that they had any suspicion that they 

 were dealing with two distinct diseases. 



Taking all these facts and opinions into consideration, the Committee at an 

 early period adopted the provisional view that Klein and Cobbold com. 

 had before them Grouse dead from two distinct diseases — (l) plump and ,"ovUiionai 

 well-conditioned birds which had died of an acute infectious pneumonia, ^]s^~t^° 

 i.e., the acute form of Klein's "Grouse Disease"; and (2) emaciated diseases. 

 piners which had died of the results of extreme parasitism, i.e., of Cobbold's 

 Strongylosis. The Committee kept in view, however, that since there 

 is no reason why a bird already dying of Cobbold's Strongylosis to recondie 

 should not become infected with, and succumb to, Klein's infectious ,?'f °'^ •., 

 pneumonia, it was possible that the piners examined by Klein might Cpbboid's 

 also be cases of the acute infectious pneumonia, which had stepped 

 in and made an end of their already diseased existence. 



It would have been obvious to Dr Cobbold, if he had ever really seen a clear 

 case of a Grouse which had died in good condition, well up to average weight, but 

 with pneumonic lungs, that its death must have been due to some more acute 

 cause than the mere presence of nematodes in the gut. 



» Cobbold, " Grouse Disease," pp. 24, 25. 2 /j^y_ 



