22 THE GROUSE DISEASE chap. 



and from what has been stated just now it is clear 

 that it would amount to an extremely distant chance 

 to get some of those capillary plugs in the droplet of 

 blood. In 1888 I made a good incision with sterile 

 scissors or scalpel into the substance of the lung or the 

 liver — the lung or liver as a whole having previously 

 been well dipped in saturated solution of mercuric 

 bi-chloride to disinfect the surface — and from the 

 cut surface a particle of the tissue was cut out with 

 sterile scissors and used for cultivation ; here, of 

 course, the chances of hitting one of the capillaries 

 containing the bacterial masses are very much greater. 

 And working on this plan I have obtained sufifiQJent 

 evidence to enable me to state confidently that the 

 lung and liver of the grouse that are affected with 

 the disease in the spring and early summer con- 

 tain a definite species of bacteria forming continuous 

 masses or plugs in some of the capillary blood-vessels, 

 but that in the blood of the general circulation they 

 cannot be demonstrated. From this then it follows 

 that the bacteria find their way into the lung and 

 liver, in whose capillaries they settle and by their 

 multiplication produce those embolic plugs. This 

 is nothing exceptional, since we know of infectious 

 diseases, both acute and chronic, in which the specific 

 microbe does not thrive in the circulating blood, i.e. 

 does not find in this a suitable nidus, and is there- 



