191 



Rabiger," 1905, states that experiments with Loeffler's mouse 

 typhus bacillus and the bacillus of Danysz virus have been carried 

 to the conclusion that these bacterial preparations must be charac- 

 terized as practically worthless. 



In 1903 Neumaim discovered in Denmark a rat-killing bacillus, 

 which has been placed on the market by a society under scientific 

 control under the name of "ratin." Feeding experiments with this 

 bacillus were tried under conditions as nearly natural as possible 

 upon white mice, gray house mice, long-tailed field mice, and gray 

 rats. The experiment animals were fed with cubes of white bread 

 impregnated with virulent cultures. White mice show the least 

 power of resistance, since they die within six days; house mice died 

 in six to nine days; the greater part of the rats died from the sixth 

 to the sixteenth day after feeding; a small percentage lived. The 

 long-tailed field mice, which are shown to be insusceptible to LoeflBier's 

 bacillus, also remained perfectly healthy after repeated feedings with 

 bread infected with ratin. 



Brooks,'' 1908, reports the results of tests made with azoa on rats 

 and mice, both in captivity and. at large, but without any apparent 

 discomfort to the animals. One of the tests is described as follows: 



A supply of the azoa was obtained direct from the laboratories of the manufacturers. 

 On July 27, 1907, while the material was yet fresh, three young Norway rats were caught 

 and kept confined in a large wire rat-trap. Beginning with the date given, and for a 

 period of forty days thereafter, azoa was fed to the rats at intervals of a few days until 

 ten 75-cent bottles had been consumed. The rats ate the cracked grain with which the 

 virus was mixed very readily, and other food was denied them each time the azoa 

 was given until every particle was eaten. At the end of the forty days the rats were 

 still apparently in a healthy condition, and were removed from the trap and killed 

 with a club. 



Thompson,"^ 1906, states that three laljoratory attempts have been 

 made to destroy rats with imported strains of Danysz rat virus with- 

 out success. Danysz having arrived at Sydney to study a similar 

 method of destroying rabbits, the opportunity was taken of making 

 a further attempt under his supervision with virus which had been 

 imported and subsequently increased to the requisite degree of viru- 

 lence, and had been placed at Thornpson's disposition. The grounds 

 of the Gladesville Asylum, a large institute for the insane, were chosen 

 for the tests, which were conducted by Dr. R. J. Millard. 



« Rabiger, H.: Ueber Versuche zur Vertilgung der Ratten durch Bakterien. Landw. 

 Woch. f. d. Prov. Sach., 1905, p. 142. Rev. by Stift in Centblt. f. Eakt., 2 Abt., vol. 

 15, 1905, p. 86. 



6 Brooks, Fred E.: Notes on the habits of mice, moles, and shrews. A preliminary 

 report. Bull. 113, W. Va. Univ. Agric. Exper. Sta., Morgantown, W. Va., Jan., 1908. 



c Thompson, J. Ashburton: Report of the Board of Health on plague in New South 

 Wales, 1906. On a sixth outbreak of plague at Sydney^ 1906. Legislative assembly, 

 N. S. W., 1907. 



