670 



Bacillus Murium 



mice that had eaten the bread, but also infected others that ate their dead bodies, 

 the extermination progressing until scarcely a mouse remained. 



In discussing the practical employment of this bacillus for the satisfactory de- 

 struction of field-mice, Brunner* calls attention to certain conditions that are 

 requisite: (i) It is necessary, first of all, to attack extensive areas of the invaded 

 territory, and not to attempt to destroy the mice of a small field into which an 

 indefinite number of fresh animals may immediately come from surrounding 

 fields. The country people, who are the sufferers, should combine their efforts so 

 as to extend the benefits widely. (2) The preparation of the cultures is a matter 

 of importance. Agar-agar cultures are most readily transportable. They are 

 broken up in water, well stirred, and the liquid poured upon a large number of 

 small pieces of broken bread. These are then distributed over the ground with 

 care, being dropped into the fresh mouse-holes, and pushed sufficiently far in to 

 escape the effects of sunlight upon the bacilli. Attention should be paid to holes 

 - in walls, under railway tracks, etc., and other places where mice live in greater 

 freedom from disturbance than in the fields. (3) The destruction of the mice 

 should be attempted only at a time of the year when their natural food is not 



Fig. 264. — Bacillus typhi murium (Migula). 



plenty. By observing these precautions the mice can be eradicated in from eight 

 to twelve days. In the course of two years no less than 250,000 cultures were 

 distributed from the Bacteriological Laboratory of the Tierarznei Institut in 

 Vienna, for the purpose of destrojdng field-mice. 



The bacilli are not pathogenic for animals, such as the fox, weasel, ferret, etc., 

 that feed upon the mice, do not affect man in any way, and so seem to occupy a 

 useful place in agriculture by destroying the little but almost invincible enemies 

 of the grain. 



A similar organism, secured from an epidemic among field-mice and greatly 

 increased in virulence by artificial manipulation, has been recommended by 

 Danyszf for the destruction of rats. When subjected to a thorough study by 

 Rosenaut this organism was found to be identical with Bacillus typhi murium. 

 It is, however, too uncertain in action to be relied upon for the destruction of rats 

 in plague-threatened cities for which it was suggested. 



* Centralbl f. Bakt., etc., Jan. 19, 1898, Bd. xxni, No. 2, p. 68. 

 t "Ann. de ITnst. Pasteur," April, 1900. 



t "Bulletin No. s of the Hygienic Laboratory of the U. S. Marine Hospital 

 Service," Washington, D. C, 1901. 



