STUDIES ON FOWL CHOLERA 



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to reproduce more faithfully the experimental conditions under 

 which he worked the writer inoculated intravenously two rabbits 

 with 1 cc. per kilo body weight of a forty-eight-hour killed broth 

 culture of the highly virulent strain 48 killed by heating at 62° 

 for 20 minutes. The results are indicated in the accompanying 

 table. 



From the data presented in the tabulation it is apparent that 

 the intravenous injection of killed culture produced no indications 

 of strong toxicity; moreover, that inoculation with a relatively 

 large amount of living culture produced fatal results only after a 

 period of fourteen hours, indicating no strong toxic action in 

 the unmodified virus. 



In addition to the tests mentioned above, another experiment 

 may be cited which demonstrates even more conclusively the 

 absence of a strong extra-cellular toxin derived from a highly 

 virulent culture of B. amsepticus growing in broth culture. 



A rabbit was inoculated by the intra-abdominal route with 

 0.001 cc. of a broth culture of strain 48 and died in fourteen hours. 

 The culture was regained from the heart's blood and plated. A 

 colony was subcultured into flasks of chicken broth. One of 

 these was grown at 37°C. for forty-eight hours and passed through 

 a Berkefeld N-candle under suction. The filtrate was tested for 

 sterility as follows: Ten 0.1 cc. samples of filtrate were trans- 



