16 



MASS. EXPERIMENT STATION BULLETIN 295 



Table 1L — Filtration of Infectious Laryngotracheitis Virus 



Legend: — S - Seitz filter 



V - Berkefeld V filter 

 N - Berkefeld N filter 

 W - Berkefeld W filter 



CONTINUOUS CULTIVATION OF THE VIRUS IN THE BURSA OF 



FABRICIUS 



This part of the project was designed to determine whether the virus of infec- 

 tious laryngotracheitis could be continuously cultivated in the bursa of P'abricius 

 or not, and if so, whether bacteria interfering with vaccinations could be eliminated 

 or not. Furthermore, it was deemed important to study the immunizing proper- 

 ties of the viruses as they were being continuously cultivated, in the hope that they 

 would become adapted to growth in this organ and lead to the discovery of a more 

 satisfactory immunizing agent than has been found up to the present. 



Accordingly, two viruses which had given the best results in previous bursal 

 vaccinations were selected for this study. In each of these trials two chickens were 

 inoculated in the bursa of Fabricius and the virus was transferred to the same 

 organ of two other chickens every three days. At each transfer two control 

 chickens were inoculated intratracheally with the same virus and the results re- 

 corded as indicated in Tables 12 and 13. 



Table 12. — Continuous Cultivation of Virus X in the Bursa of Fabricius 



Date 



8/27/32 



8/30/32 

 9/ 3/32 

 9/ 6/32 

 9/ 9/32 

 9/12/32 

 9/15/32 

 9/19/32 

 9/22/32 



s^Died 



