MISCELLANEOUS: STIMULI UNDERLYING TUMOR-FORMATION 517 



A 



I f 



B 





FIG. 388. A. Hyperplasia in a lenticel en a young olive shoot due to treat- 

 ment (March 4, and several times after that) with petrolatum. Response rather 

 slow. From an unstained free-hand section. Photographed March 28, liUS. 

 S mm. obj., 4 oc., bellows at 45. B. Cross-section showing a normal lenticel. 

 Olive shoot of same age as *4. The dark color under the lenticel is due 

 to chlorophyll. 



