312 THE ZOOLOGIST. 



individuals which had died of the disease, and which swarmed 

 with bacilli. The first mode of infection of course was possible in 

 a state of freedom. But it was doubtful whether Field Voles in 

 a state of nature would devour the bodies of their dead comrades, 

 and feed on the brain and entrails, as they invariably do in 

 captivity. Many experienced agriculturists, however, thought 

 that they do feed on the dead corpses in the same way in a state 

 of freedom, though others doubted whether this supposition was 

 correct. Again, it seemed uncertain to me whether the voles 

 would run from one burrow to another, and thus spread the 

 disease. It was therefore not enough to infect a few mice, set 

 them at liberty, and wait to see whether the disease would be 

 propagated in the course of some weeks, as within the narrow 

 limits of a cage ; but it was needful also to devise some mode of 

 infection in which the propagation of the disease by cannibalism 

 should not be the main object. Doubtless the result would be 

 obtained with much greater certainty if the bacillus were scattered 

 with food in the most wholesale manner over all the lands infested 

 by the voles in order to accomplish the destruction of the majority 

 by primary infection. As I was doubtful (a doubt fully justified 

 by subsequent experiments) whether the exhaustive undertaking 

 which I contemplated in Thessaly could be carried out without 

 my personal supervision, I promised his Excellency the Greek 

 Ambassador, M. Rangabe, that I would consent to furnish the 

 Greek Government with some preparations of the bacillus, 

 though I was unwilling to do so because I was doubtful whether 

 this means of destroying the voles could be carried out in the 

 way which I intended, and because I was afraid that some mishap 

 might occur which might have nothing to do with the method 

 itself, but which might throw discredit on this entirely new 

 bacteriological experiment. But I declared that I was quite 

 ready to carry out my own experiments in Thessaly myself if the 

 Greek Government would defray the travelling and hotel expenses 

 for myself and an assistant. On April 1st I received a telegram 

 informing me that the Greek Government invited me to come to 

 Greece on the terms which I had offered. But, before definitely 

 accepting the invitation, I wished first to ascertain a very im- 

 portant point, which was taken for granted, but which my 

 experiments on other species of mice showed to be by no 

 means necessarily the case, whether the Field Vole which had 



