PLATE is 
i, 2.—Intemodesof Rtcinus communis , showing the result of injecting a 5 per cent 
solution of cane sugar into young intemodes of the main axis, the stimulus being con¬ 
fined to the injected intemodes. (1) Ceiling of lower injected intemode and (2) ceil¬ 
ing and upper part of middle injected intemode, both showing conspicuous prolifera¬ 
tions—that is, numerous small tumors. That at X is where the needle entered. There 
is no visible killing of the pith surface in the upper part of either intemode. Injected 
on August 7, 1916. Photographed on October 19, 1916. X3. 
3. —Cross section of upper part of a young Ricinus stem showing pith cavity lined 
by a thin sheet of glistening white cell proliferations due to the injection of ammonium 
tartrate. Time, nine days. X10 (circa). 
4. —Side view of figure 3, further enlarged to show the cells. 
