CULTIVATION OF THE VIRUS OF INFECTIOUS LARYNGO-TRACHEITIS OF CHICKENS

Abstract

Li and Rivers vaccine-virus medium .(minced chick embryo+ Tyrode''s solution) and bac-teriologically sterile Berkefeld-V filtrates of infusion-broth suspension of tracheal exudate from an infected chicken, were used. Active virus was demonstrated in a number of cultures separated from the original by a sufficient number of generations, so that virus could be present only by multiplication. In one series, still carried at time of writing, virus was demonstrated in cultures of the 22nd generation. Here, multiplication of virus was more than 5 X 1023. Virulence of culture virus equalled that of the original virus filtrate.