DESTRUCTION OF MICE IN THE FOREST BY THE 

 LOFFLER RAT-TYPHUS BACILLUS^ 



By Dr. Gerhardt, CoblEinz 



(Translated by E. C. Rogers) 



The beech nut crop of 1909-10 was not very abundant, has suffered 

 further considerable loss through many animals. Wild pigeons and 

 mice appeared in great numbers and were most injurious. Particu- 

 larly in the seeding places, in which soil-preparation by machinery 

 or hoeing took place, the beechnuts disappeared rapidly. The loss 

 was the more noticeable where artificial sowing was done with pur- 

 chased seed. 



After the beginning of February, wherever an uncommonly strong 

 appearance of mice had been noted, I brought into use in 11 guard 

 districts on an area of 170 hectares the rat typhus cultures. These 

 were procured from the Bacteriological Instifute of the Agricultural 

 Chamber at Borme, and were laid out according to plans locally agreed 

 upon with the head of the division, Dr. Krantstrunk. Such guards as 

 were not present at this oral instruction, were later informed as to 

 the use and procedure with the cultures by, the officer from the institute 

 who delivered them. 



For 483 marks there were obtained sufficient cultures in glass test 

 tubes for use. An average of 7.3 tubes were used per hectare. Conse- 

 quently, each hectare cost 2.83 marks for the means of destruction. 

 The cost of laying out, including the buying of the necessary white 

 bread, amounted altogether to 485.71 marks, consequently 2.85 marks 

 per hectare. An average of 0.62 mark for bread was necessary per 

 hectare. The laying out places were from 0.4 to 1 square meter in 

 size. There were about 400 of these per hectare. After removal of 

 the weed cover a square meter spot showed from 1 to 4, on an average 

 of possibly 2 mouse holes. On each spot was placed a handful of 

 the bread crumbs infected according to instructions, which was then 

 covered by replacing the leaves. These spots remained visible for days 

 through the disturbed appearance of the leaves. After several days 

 the crumbs everywhere had almost completely disappeared, and had 



'Allgem., F. J. Z. 87 (1911) :37. 



283 



