304 TfiE ZOOLOGIST. 



On Nov. 14th, four days after the inoculation, the second 

 Field Vole died. At the point of inoculation I found a yellowish 

 fibrinous gathering containing enormous masses of bacilli, partly 

 truncated, and partly enclosed by large colourless cells. Other- 

 wise the result of the examination was as in Field Vole No. L. 

 A preparation of the liver exhibited very numerous bacilli, the 

 presence of which was also proved by cultivation. 



The three Field Voles which had fed on No. 1 died on the 

 17th, 18th, and 20th November respectively. They all exhibited 

 the same conditions, and in particular the mesenteric glands were 

 greatly enlarged, and of a brownish red colour. 



The third Field Vole, which died on the 20th November, was 

 again thrown into a cage with three others. These three all 

 died on the 28th and 30th November, and on the 2nd December, 

 after eight, ten and twelve days respectively. They appeared 

 lively till about two days before their death. After this they 

 appeared less lively, and at last sat huddled up, with erect hair. 

 They were hardly dead when their comrades made them a source 

 of death to themselves by devouring them. It is well known that 

 Field Voles devour the dead or weak and sickly individuals of 

 their own species. After this first experiment, I could no longer 

 doubt that the Arvicola was at least as susceptible to the bacillus 

 as the white Mus. 



I made so many experiments in infecting Field Voles that 

 I cannot repeat them all in detail. I will only say that the 

 infection per os invariably succeeded, whether I threw them 

 potato-cultivations, bread moistened with bouillon-culture, or only 

 poured a few drops of the latter into the cage ; the animals 

 invariably died from eight to twelve days afterwards, and in every 

 carcass the typical bacillus was present. 



This proof of the great susceptibility of Field Voles to this 

 bacillus, and their easy destruction by this means, seems to me 

 to be of great practical importance to agriculture. In many 

 districts these Field Voles are a veritable scourge. They cause 

 enormous losses by their fecundity and voracity. Brehm gives 

 an appalling picture of their habits and their importance to 

 Agriculture in his Thierleben (vol. ii. p. 388). He says : — 



" Their food consists of every sort of vegetable substance. When they 

 can obtain seeds they feed only on these, but at other times they content 

 themselves with fresh grass and herbs, roots and leaves, clover, fruits and 



