miscellaneous: stimuli underlying tumor-formation 529 



Fig. 398. — From same series as Fig. 397, showing ruptured and unruptured 



hyperplasias produced in 18 days under the skin of a potato tuber expose I to 



dull light on wet cotton in a confined air space at 25°C. Block sealed into the test 



tube April 26, 1919. Photographed May 14. X 5. Acidity of whole flesh + 35. 



34 



