320 THE ZOOLOGlS*. 



These gentlemen, accompanied by a number of pupils, visited the 

 localities which were most severely threatened in the neighbour- 

 hood of Velestino and Larissa, and began to deal with the voles 

 in the middle of May. The measures taken by these gentlemen 

 previous to our arrival consisted in flooding the infested arable 

 land with water, in scattering poisonous food, in sinking large 

 tin vessels in the ground, and in pouring bisulphide of carbon 

 (Schwefelkohlenstoff) into the "runs." But the flooding of the 

 "runs" could only be carried out in a few places, partly for want 

 of water, and partly because the local conditions were unsuitable. 

 However, what the Committee were able to do was attended with 

 good results. They reported that the bisulphide of carbon had 

 succeeded well. In using it, the first step taken was to close up 

 all the openings to a colony. Next day all the newly-opened 

 holes but one were closed. The nozzle of an injection-tube was 

 inserted into this one open hole, and a measured quantity of 

 bisulphide of carbon, of about 10 cm., was forced into the "run" 

 by a special apparatus. It was asserted that all the voles inside 

 were killed in a few seconds by the vapour diffusing itself through 

 the " runs." The Committee informed us that they had found a 

 great many dead mice on digging up a burrow that had been thus 

 treated. But the use of bisulphide of carbon was also only 

 possible in certain suitable localities, that is, only where the 

 holes in the ground were visible ; for the fallow-fields were 

 covered almost everywhere with great thistles almost as tall as a 

 man, and the voles prefer to make their holes under cover of 

 these. Again, if all the holes of a colony are not closed before 

 the injection of the bisulphide of carbon, the vapour, and probably 

 the animals too, will escape through the openings which have 

 been left. At the time of our arrival the first supply of bisulphide 

 of carbon furnished by the Government had been exhausted, and 

 it was very difficult to obtain the large supplies which were 

 ordered from France via Marseilles, for no vessel would carry on 

 board a large quantity of this dangerously-inflammable substance. 

 Moreover, the use of bisulphide of carbon became unadvisable 

 about the end of April, because at this time of year the heavy soil 

 had already become parched and cracked by the sun, and the 

 vapour escaped through the fissures, without doing any execution 

 in the " runs." As the heat increased, too, there was much loss 

 of material. Bisulphide of carbon boils at 46'5° C. In the open 



