Certain Conditions Determining Enhanced Infection with the Rabbit Papilloma Virus

The infection of normal or hyperplastic rabbit skin with the papilloma virus can be greatly enhanced by protecting the scarified and inoculated area with a layer of paraffined gauze until healing occurs. In this way the necrosis which follows upon scarification and also the scabbing are almost entirely prevented and in consequence epithelial regeneration is usually complete within 24 hours. Not only are many susceptible cells provided to the virus far earlier than would otherwise be the case,-and collateral tests have shown that it becomes associated with them within a few hours instead of after many,-but the inoculum is itself conserved, instead of becoming largely lost amidst necrotic tissue and scab, as under ordinary circumstances. The effective titer of the virus is increased by the procedure from 10 to 100 times over that attained when hyperplastic skin is allowed to dry after inoculation. Since the results under the latter circumstances are 10 to 100 times better than those when normal skin is treated in the same way it follows that a 100- to 10,000-fold increase in the effectiveness of the virus has now been obtained.