INFECTIOUS TRACHITIS 



37 



TaBI.K 7. RkSULT3 of INOCULATION' WITH UNFII.TERED GuANBY VIRUS. 



Controls on Experiments with Granby Virus 



White Leghorn fowl 30996 and Plymouth Rock fowls 30997 and 3099S 

 were controls on all of the fowls on the Granby virus experiments, be- 

 ginning with the second transfer of the virus on Noveml^er 27, 1929. A 

 record of the experiments with the controls appears in Table 8. 



The controls indicate that cross infections did not occur in the experi- 

 ments on the Granby virus. All of the controls were later found to be 

 susceptible to infectious trachitis. 



Experiments with Chronic Field Cases Under Laboratory Conditions 



During the winter of 1929-30, fowls sick with diseases simulating the 

 Granby outbreak of infectious trachitis, were received from the following 

 places in Massachusetts: — Leverett, Westwood, Gardner, South Lincoln, 

 and Watertown. In all of these cases the disease was running a chronic 

 course in laying fowls. Viruses from these birds produced either chronic 

 symptoms or no indications of disease when fowls and chickens were 

 inoculated intratracheally under laboratory conditions. The results were 

 not always as clear-cut as with the Granby virus. The mortality was 

 low. It was impossible to transmit any of these viruses in the laboratory 

 in a satisfactory manner. Most of the time the temperatures of the 

 inoculated birds were normal. The most common symptoms were lacrima- 

 tion of the eyes, cough, and pseudomembrane in the larynx. None of 

 the birds ceased to eat. Seme of the fowls continued to lay during the 



