Summary
The growth potential of nine avian lymphoid tumor strains involving 50 samples was tested in the fresh state, and after freezing and storage at low temperatures, by inoculation of tumor suspension into a total of 1,350 White Leghorn chickens.
All tumor strains survived freezing and storage, but there was considerable variation among samples and strains in the viability of frozen tumors. There appeared to be a direct relation between the growth potential of tumors in the fresh state and that after freezing and storage.
There was no evidence of a change in the growth potential of frozen tumors during long continuous storage at temperatures of from -65°C. to -76°C. A tumor sample tested 2,028 days after freezing produced tumors in all chicks inoculated, in a period of 8.2 days (average).
Data were presented which show that the activity of avian lymphoid tumors which had been frozen slowly was due to the survival of viable tumor cells and not to the activity of a virus.