Two intraperitoneal injections of either infectious or non-infectious rabbit papilloma suspensions actively immunize rabbits against papillomatosis. The capacity of the non-infectious suspensions to immunize is considered as evidence that they contain papilloma virus even though none can be demonstrated by the usual infection test.

Quotations: Report of the President of Harvard University ......... 228 Special Articles: A Factor in Domestic Rabbit Papilloma Tissue Hydrolyzing the Papilloma Virus Protein: PROFESSOR J. W. BEARD and OTHERS. The Respiration of Elodea: R. R. RONKIN and PROFESSOR S. C. BROOKS. On the Size and Shape of the Tobacco Mosaic Virus Protein Particle: PROFESSOR VERNON L. FRAMPTON ........ ................