Obviously, if the Field is right now, Dr. Klein did not discover the grouse disease bacillus. And if he did discover it, any fowls dead from or sick with disease may at once be regarded as victims of something else; and other gallinaceous birds must be suspected in consequence of being refractory to the grouse disease.

The author’s belief is that Dr. Klein did discover the bacillus, although he failed to prove it, and that his experiments on buntings, fowls, and other creatures went to suggest that the grouse is not a natural host of the bacilli, that it or its virus becomes attenuated or weakened every time it passes through a grouse, but that, on the contrary, it becomes more virulent in passing through buntings and yellow-hammers. This was suggested by the weakness of the virulence from the bacilli cultivated from the diseased autumnal grouse after a severer spring outbreak, and it is also suggested by the fact that in such cases the grouse do not die rapidly, and that it is a slow disease from which perhaps some grouse recover; whereas they do not recover in the spring. The writer’s suggestion is, therefore, that when the bacillus is carried from grouse to grouse it may be weakened, but that in spring it is not originated in the grouse, but in some creature unknown, and possibly a migrant bird of the bunting, hammer, or finch families. The importance of finding this out, and testing the attenuation theory more thoroughly in live grouse, is obvious, for if it is true that the blood of successive grouse gradually weakens the bacilli or their virus, then it is clear that the safety of grouse will be the constant presence of some few diseased grouse on the moor.

The author only dwells on this aspect because it is not receiving as much attention as some others, which are constantly being discussed, and are therefore less necessary to mention.

At present thought is mostly in the contrary direction. But it is to be hoped and believed that the Commissioners will investigate every possible view from a scientific standpoint, and more important still, from a practical one. For instance, if on a disease affected moor grouse can be kept in health in a pen of midge-proof netting, we shall hardly need to know where the midge gets his poison, but shall be exceedingly likely to dry up his breeding-places and exterminate him as nearly as may be.

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