PLATE 16 
1. —Eight small tumors and various strands in an unopened intemode of Ricinus 
contmunis t which showed no surface injury of the pith. On the opposite side of the 
pith cavity facing these nodules was a continuous white tumor an inch long. This 
is the first internode above one into which was inserted a small sterile glass tube hold¬ 
ing 0.2 c. c. of a 5 per cent solution of monobasic ammonium phosphate, which slowly 
gives off alkaline vapors, and between the two intemodes there was % inch of solid 
node tissue. Tube inserted on August 8,1916. Photographed on August 30. X5. 
2. —Section of one of the tumors shown in figure 1. Four unopened intemodes in 
this stem showed effect of the vapor—namely, the first one below that which held the 
tube and the three immediately above it. 
