56 THE GROUSE DISEASE chap. 



it will be found that the particle, though apparently- 

 dry, nevertheless still includes living bacilli ; for 

 on inoculation of broth with it, and after incubation, 

 the broth becomes turbid with the grouse bacilli, a 

 new growth having taken place. This is evidently 

 due to the fact that the particle becomes dry on 

 the surface only ; the central portion not becoming 

 quite dry, being protected by the outer dry part, 

 still harbours living bacilli. The larger the particle, 

 the greater the chance of the bacilli surviving in the 

 centre. Now this may be applied also to the con- 

 ditions obtaining on a moor. A bird dies of the 

 disease on the moors. Its body becomes lacerated 

 or opened in some way, by animals of prey or 

 otherwise, portions of the lungs and liver dry up, 

 and may retain living bacilli which may remain 

 sheltered for some time, and, when finding access to 

 a suitable bird, say next spring, may set up the 

 disease, and thus produce a focus for the develop- 

 ment of the epidemic. I do not mean to say that 

 such an occurrence can be or has been proved, but it 

 must be admitted that such an occurrence is possible, 

 and that it is justified by the experimental facts 

 with regard to the influence of incomplete drying. 



From all that has preceded it will be evident 

 that the only measures of dealing with the disease in 

 order to check its spread and epidemic appearance. 



