BY DR. OSCAR KATZ. 583 



inhabit the normal intestinal canal of pigeons, perhaps also of 

 other birds, similarly as the septic vibrio (the bacillus of malignant 

 oedema) is always present in mammals. In such state the microbes 

 are not virulent enough to do any harm to their host, or to other 

 poultry into which they are inoculated ; they are, however, able 

 to cause disease and death in the case of very susceptible, though 

 healthy, animals, namely rabbits and " Ziesel " (also rodents, Genus 

 Spermophilus). Transmitted through the body of a rabbit or a 

 " Ziesel," they attain such a strength that they are aV)le to kill 

 pigeons and fowls ; on the other hand, fowls can be rendered 

 immune against deadly infection by chicken-cholera bacteria, by 

 means of the inoculation of certain doses of the above virus (passed 

 through rabbits, e.g., from the intestines of healthy pigeons). 

 With regard to the important question : under what conditions 

 the originally harmless bacteria exhibit their dreaded epidemic 

 virulence, Gamaleia favours the view of the " removal from the 

 intestinal canal of all mesoderm-phagocytes which must be engaged 

 in the digesting of large quantities of the introduced saprophytes." 

 He proposes to strike out the altogether inappropriate designation 

 " bacteria of chicken-cholera," and to substitute the more scientific 

 name " bird-septicsemia." The name for the concerning microbes 

 shall be coccobacillus avicidus, which must be assigned to the 

 entosaprophytes which are also facultative parasites. 



After having taken information of Gamaleia's interesting paper 

 I wished to know whether I should succeed in proving' the occur- 

 rence of attenuated forms of the bacteria of chicken-cholera in 

 normal pigeons, on Australian soil. The tests were made on wild 

 rabbits which throughout were known to me as highly accessible 

 to virulent "chicken-cholera." The results, however, did so far 

 not confirm Gamaleia's statement ; they were all negative, as 

 shown by the following list of experiments. At the end is mentioned 

 the examination of a chick, with the same result. 



