52 



MASS. EXPERIMENT STATION lUT.I.KTIN 273 



These experiments indicate that the virus of infectious trarhitis does 

 not live more than a day or two outside of live birds when exposed to 

 light, air, and decomposition. However, in the winter under freezing 

 conditions, such viruses may last for five days or a week, and under 

 especially favorable conditions of freezing and drying they may even 

 last longer. 



Carriers 



Table 24' contains some data on acute and chronic carriers, which show 

 that the virus was present in the tracheal exudate in all but a compara- 

 tively few of the acute cases of the disease. It was also found in the 

 cloacal contents of three of the birds inoculated with the first California 

 virus and four of the cockerels and pullets treated with the first New 

 Jersey virus. The virus of infectious trachitis was not demonstrated in 

 the intestinal contents or in the blood of any of the birds studied" in 

 these experiments. 



Two chronic carriers were found harboring the virus in the tracheal 



Table 24. — A tabulation of the experuients ox cakrieus. 



Substarxe exarri ed 



Nan;e 

 cf 



Course 

 of ti e 

 ciseose 



Numl er cf I irds 



Tctal 

 exarri ed 



Virus 

 I te.-e' t 



Virus 

 al fer.t 



Tracheal exiidate 



Intestinal co-te^ts. 



Cloacal coiiter.ts. 



I Granby 



Hadley 



Leverett , . . . 

 \\'ei=t\vood . . 

 So. Li. .coin. 

 Card- er. . . 

 Watertown. 



Acute 

 Chroric 



Cl.rot ic 



Cliroi ic 



Chror.ic 



Chronic 



Chronic 



Chronic 



Acute 

 Chronic 



California I . . . 



New Jersey I.. 



f California I f Acu 



I New Jersey I.. . . I Acu 



i California I. . . 

 New Jersey ]....< ,,, 

 I Chror.ir 



Acute 

 Chronic 



.'.cute 

 Chroi.ic 



15 

 8 



10 

 .3 



:^o 



2 

 144 



62 



