314 THE ZOOLOGIST. 



I perceived at the first glance that the Thessalian Field Vole 

 was undoubtedly different from our Arvicola arvalis. It was 

 considerably larger, paler in colour, with large shining eyes, and 

 a very short tail. It had a much more vigorous- and rat-like 

 appearance than our Field Vole.* It was enough to damp my 

 expectations considerably to discover that I had to deal with an 

 obviously different, though allied, species. Before we could think 

 of undertaking any further measures and preparations for the 

 practical application of my method in Thessaly, it was necessary 

 to ascertain whether this species was susceptible to infection by 

 the bacillus, especially per os. Three of these Field Voles were 

 immediately subjected to subcutaneous inoculation with some of 

 the cultivated bacillus which I had brought with me, and three 

 others were fed with pieces of bread dipped into some virus 

 diluted with water. When I afterwards visited his Excellency 

 the Prime Minister, I informed him of my observations respecting 

 the species, and declared that before anything further could be 

 attempted, we must wait for the result of the experiments which 

 had just been commenced. 



The Director of the Agricultural Department of the Ministry, 

 M. Gennadius, then added that the scientific determination of the 

 species was rather difficult, and that the Thessalian Field Vole 

 exhibited several of the characters of Arvicola arvalis, but that it 

 might possibly be Arvicola Savii. 



The question of the susceptibility of the Thessalian species 

 asserted itself, to my great joy, much more rapidly and favourably 

 than I had dared to hope. One of those inoculated died in two 

 days, the second in three, and the third in three and a half days. 

 All the bodies exhibited quantities of bacilli in the internal 

 organs, which could also be obtained from them by the ordinary 

 methods of cultivation. The first animal fed with infected matter 

 died in five and a half days, and a second in seven days; both 

 exhibited the characteristic pathological and anatomical changes 

 of "mouse-typhus," viz., enlarged spleen, parenchymatous liver 

 and kidneys, and inflamed and swollen mesenteric glands. 



From these results it appeared that the Thessalian vole was 

 even still more susceptible to " mouse-typhus" than our Arvicola 



'■'■'- Later on I propose to publish an exact description of the species, when 

 I reoi Lve the specimens which I have had preserved in alcohol. 



