miscellaneous: tumors in absence of parasites 491 



abnormal elevation of temperature and excessive water sup- 

 ply," combined with weak illumination. With this view 

 Atkinson agrees. In the last edition of his book Sorauer 



Fig. 368. — Cross-section, well above the leaf surface, of acetic acid tumor 

 on cauliflower leaf 7 days after exposure. Surface covered by an epidermis. 

 Block 1289. Fixed September 28, 1916. The exposure was for >2 hour in 10 

 cu. ft. of air space to vapor from 10 cc. of Carnoy's fluid on a warm bath (about 

 65°C.). 8 mm. obj., 4 oc, bellows at 50, and enlarged ^i by engraver. Photo- 

 micrograph by the writer. 



places intumescences under diseases due to "excessive moisture 

 of the air." 



Other observers regard strong light as favorable and specifi- 

 cally on grape leaves (Viala and Pacottet, /. c.) "excess of light in 



