MISCELLANEOUS: STIMULI UNDERLYING TUMOR-FORMATION 533 



FIG. 401. Block of pared sterile potato flesh exposed to same light, temperature 

 and atmosphere as Fig. 400 and in all respects like it, except that the lower 

 hyperplasias have fused and ruptured encircling the entire base of the shoot. 

 Photographed April 10. X 5. 



