BY DR. OSCAR KATZ. 573 



chicken-cholera are not known to form spores or seeds (as, for 

 instance, the anthrax-bacilli do), by means of which they are able 

 to live under adverse circumstances. 



I have to record three series of experiments. 



The general plan of procedure was as follows : — A number of 

 silk-threads — of the kind used in surgery — of 1 centimetre in 

 length and |^ to | millimetre in thickness, were placed in a sterile 

 cotton- wool-plugged test-tube, and after having been thoroughly 

 moistened with distilled water, were exposed in the steam-steriliser 

 to steam of 100°0. (212° Fahr.) for two hours. The moisture 

 remaining in the silk-threads and in the tube, was got rid of by 

 placing the latter in a copper-box heated up to 100 — 105° C. 

 (212 — 221° Fahr.) as long as required. 



The virulent material to be tested for its resistance to desicca- 

 tion consisted, on the one hand, of blood taken from the liver of 

 rabbits which died on inoculation, on the other hand, of fresh 

 broth-cultures derived directly from blood of rabbits newly dead 

 of " chicken-cholera " on inoculation. 



The silk-threads referred to above were impregnated with either 

 blood or culture. 



In case they were to be impregnated with blood, they were 

 placed on cut-surfaces of the liver, where they remained until they 

 were completely soaked. The livers of all the rabbits used were, 

 I may mention, not otherwise diseased. 



In case the threads were to be charged with broth-culture, a 

 small quantity of the latter was placed, by means of a sterile 

 pipette, in a sterile watch-glass, where they remained for some 

 time. 



The silk-threads, thus treated either with blood or culture, were 

 then transferred to different places where they could dry up, as 

 will be seen from what follows below. Within certain intervals a 

 silk-thread of both the one and the other description was inocu- 

 lated into a rabbit each, whereby the virulence or non-virulence of 

 the administered material was to be ascertained. The threads 



