PLATE 27 
1. —Cross section of a normal internode of the same age as figure 2. 
2. —Main axis of plant 5 of Ricinus communis , injected August 15, 1916, with 1 to 
1,200 ammonia water. Cross section of fourth intemode above the uppermost 
injected one showing a much thickened wall and nodular proliferations from oppo¬ 
site sides of the inner pith, which did not show any dead cells. Every one of the 
four internodes above the uppermost injected one showed striking proliferations 
. from the side walls and floors and no specking of the pith—that is, no surface injury. 
Photographed on September 11. X 4. 
3. —Main axis of Ricinus plant 5, injected with 1-to-1,200 ammonia water, showing 
nodular proliferations from the ceiling and thickened sides of the uppermost injected 
intemode. There was also a sheet of proliferation 1 mm. thick over the whole inner 
surface of the intemode, and on this there were about 50 protuberant small tumors 
(glistening white cell masses). Inhere was no dark specking of the pith, but the 
deeper layers were white—that is, permeated by air. The floor also bore nodules 
like the ceiling. Photographed on September 11. X5. 
