FAMILY CHARONACEAE 



12SI 



and vice versa. Immunization to this 

 virus does not decrease susceptibility to 

 comb or mouth form of fowl pox. 



Thermal inactivation : At 60° C in 1 

 hour ; not at 56° C in 30 minutes. 



Filterability : Passes Berkefeld, Cham- 

 berland L3, and Seitz filters. 



Other properties : Particle diameter 

 calculated from filtration experiments to 



be 80 to 120 millimicrons. Not inacti- 

 vated in 30 minutes in 1 ; 50,000 methylene 

 blue solution in 2 mm layer 15 cm from a 

 300 candle-power filament lamp. 



Literature : Burnet, Med. Jour. Aus- 

 tralia, 30, 1943, 313-314; Burnet and 

 Ferry, Brit. Jour. Exp. Path., 15, 1934, 

 56-64; Doyle, Jour. Comp. Path, and 

 Therap., 40, 1927, 144-169. 



