light indentation was visible in the center of the tumor while the edge thereof remained hard the healthy surroundings of the dorsal tumor began to loosen up from the base after the application of additional ultrasonic vibration on the third day of the treatment period the tumor showed steady healing with a tender scar formation the lateral tumor was allowed to grow to a full sized tumor before ultrasonic vibration began the tumor was large inflamed and deeply rooted in the side muscles of the right rear leg of the mouse and was interwoven with healthy tissue the top surface of the tumor was flat the skin of the tumor was thin but taut and shiny the back corner of the tumor showed a fresh excision spot shortly after the ultrasonic vibration treatment began the tumor showed a swollen reaction the surface was grayish white and excretion of a viscous paste was observed two days later the tumor was still swollen but softer in appearance it was covered with a very thin layer of fine tissue and showed no ulceration one week later the entire lateral tumor except for a small crust covered area had a healthy appearance at certain points under the crust a secretion was observed approximately one month later the tumor was completely separated from the base and in its place there was a fine scar with a light indentation in the center the papilloma located near the dorsal tumor showed a complete fragmentation within ten days after.