INFECTIOUS TRACHITIS 



43 



ever, the foregoing conclusion is drawn with all reserves because of the 

 limited number of strains studied, and the data upon which it is founded 

 are given in Table 13 so that its limitation may be readily appreciated. 



The Filtrability of the First California Virus 



The larynx and trachea of four chickens, V 221.5, V 2219, V 2207, and 

 MA 94479, were used to prepare three Berkefeld filtrates and one un- 

 fiitered suspension of infectious trachitis virus, according to the metHod 

 descrilied under the filtration of the Granby virus. The results of these 

 filtration experiments appear in Tables 14, 1.5, 16, and 17. 



These experiments indicate that the first California virus did not pass 

 through tlie pores of Berkefeld \V filter in sufficient quantities to infect 

 the three chickens inoculated intratracheally with the filtrate. Sufficient 

 virus passed through the pores of the Berkefeld N filters to infect two 

 chickens; one did not contract the disease, although it was later found 

 susceptible. All three of the chickens inoculated with filtrates from the 

 Berkefeld V filters succumbed. The controls, inoculated with the un- 

 filtered portion of the suspended exudate in ]ihysio]ogical saline solution, 

 contracted infectious trachitis and died. 



