526 



BACTERIAL DISEASES OF PLANTS 



FIG. 395. Pared, sterile block of an Early Rose potato tuber sealed into 

 a test tube on wet cotton March 22, 1919, showing development of small tumors. 

 Tube kept in the laboratory in dull light at 23 to 25C. In these sealed tubes 

 there was a saturated atmosphere and, owing to continued respiration of the tuber, 

 reduction of oxygen and increase of carbon dioxide with probably some anaerobic 

 respiration leading to the production of alcohol and acids. Photographed June 

 14, 1919. X 5. 



