203 



Oettinger," in 1903, increased the virulence of the Danysz bacillus 

 by growth in an egg rendered alkaline after the method previously 

 introduced by Wiener. 



Pfreimbtner,* 1904, sees the reason for a partial failure in the appli- 

 cation of LoefHer's bacillus to the destruction of field mice. In the 

 use of a soUd medium (agar-agar), upon which the bacterial cultures 

 only grow upon the surface, too few bacteria are transferred to the 

 pieces of bread, and consequently too few virulent bacteria are con- 

 sumed by the mice. An active infection depends not upon the exist- 

 ence of virulent bacteria, but rather upon the entrance of a definite 

 number of virulent bacilh. 



The author used skimmed milk as a nutrient medium and describes 

 a series of 9 experiments and gives an estimate of the cost of the 

 process with the use of milk instead of agar. The advantage of the 

 use of milk is in the greater certainty of the results and cheapness as 

 compared with pther methods. The bread cubes impregnated with 

 skimmed milk were well taken by the mice and desiccation of the 

 cultures, which not infrequently occurs in the use of more sohd media, 

 is excluded. Notwithstanding the excessive thinning, the hquid 

 still contains many virulent baciUi. The washing out of bacilh after 

 rain is shghtly less possible as in the use of the more sohd media. 

 The action of hght, where the bread cubes contain many baciUi, is 

 insignificant, and hence the carrying out of the process in the day- 

 time is made possible. Milk is easily obtained and the thinning 

 and appUcation less bothersome. • Finally the author expresses him- 

 self against the view that the B. typhi murium causes serious diseases 

 in man. 



Teichert,'^ 1905, speaks of Loefiler's mice typhus bacillus and 

 Pfreimbtner's method of growing it upon sterihzed skimmed milk. A 

 number of experiments carried out at the bacteriological laboratory 

 of the Vreschen experiment station shows the utihty of Loefiler's 

 bacillus for the destruction of house and field mice. The long-tailed 

 field mouse was, on the other hand, not harmed by it. 



Bahr,<* 1905, gives a complete and satisfactory summary of tlie 

 Uterature upon the subject of the destruction of rats and mice with 

 bacteria, including original work of his own. 



" Oettinger, M. : Ueber die Wienerache Methode zur Virulenzsteigerung der Danysz 

 Bazillen. MuBch. med. Woch., vol. 1, 1903, p. 324. 



6 Pfreimbtner, J.: Erfahrung tiber dee Loeffler'schen Infektionsverfahren zur 

 Bekampfung der Mauseplage in einer neuen Art der An wend ung. Piililung's landw. 

 Zeit., 1904, p. 619. Rev. by Schander in Centblt. f . Bakt., 2. Abt., vol. 15, 1905, p. 502. 



<= Teichert: Die mechaniscben, chemischen und bacteriellen Kampfmittel gegen 

 Ratten und Mause. 2. Teil: Die Bekampfung der MauBe. Filhlung's landw. Zeit., 

 1905, No. 16. Rev. by Ehrenberg in Centblt. f. Bakt., 2. Abt., vol. 15, 1905, p. 503. 



<i Bahr, L.: Ueber die zur Vertilgung von Ratten und Mausen benutzten Bakterien. 

 Centblt. f. Bakt., Orig., vol. 39, 1905, p. 263. 



