INFECTIOUS TRACHITIS 41 



Continuous Passage of the First California Virus 



In order to make comparative studies of infectious trachitis from differ- 

 ent parts of the United States, outside of Massachusetts, two strains were 

 obtained from California in the spring of 1930. Since these viruses came 

 in the hatching season, it was possible to use chickens in the experiments. 

 I!: was anticipated from the results secured with the Granby virus and 

 others that chickens would be less resistant than fowls, so that the viru- 

 lence could be more uniformly maintained. Chickens between one and 

 three months of age were used in these experiments. Results are shown 

 in Table 11. 



Plymouth Hock pullet MA 30892. — The first symptoms of infectious 

 trachitis appeared on May 29. However, the resistance of the pullet was 

 marked, and possibly it would have recovered if it had not been killed 

 on June 2 for virus. At necropsy the comb was cyanotic, the face pale, 

 the feathers ruffled, but there were no indications of anemia or inanition. 

 The lungs and trachea were congested. There was no evidence of pseudo- 

 membrane in the respiratory tract. Petechiae were evident in the mucosa 

 of the trachea. The spleen was inflamed and enlarged. The liver showed 

 fatty degeneration and hemorrhagic inflammation. The case was diag- 

 nosed as infectious trachitis. 



Chicken V 2215. — A postmortem examination revealed desquamative 

 epithelial inflammation of the trachea and congestion of the lungs, but 

 pseudomembrane was absent from the respiratory tract. 



Chicken V 2219. — The face was pale, the comb cyanotic, the trachea 

 congested and inflamed without pseudomembrane. The internal organs 

 were apparently normal except the kidneys, which were somewhat hemor- 

 rhagic. 



Chicken V 2207. — The general condition of the bird was fair. A post- 

 mortem examination showed desquamative epithelial inflammation of the 

 trachea with patches of pseudomembrane in the posterior nares, pharynx, 

 and larynx. The mucous meml)rane of the trachea was moist, and pete- 

 chiae were visible in the mucosa beneath the epithelium. The lungs were 

 congested. There was fatty degeneration of the liver. This was the first 

 instance in which pseudomembrane was associated with the California virus 



