PLATE 29 
1-5.—Petiole and stem sections of plant 4 of Ricinus communis , which was injected 
on August 15 with 1-to-1,200 ammonia water. 
1. —Middle of petiole, needle entrance at X. Pith much thickened (proliferated) 
and tom away in the upper part, leaving a rough-coated hollow cylinder of prolifer¬ 
ated tissue. (See also PI. 37 and 42.) 
2, 3, 4, 5.—Parts of four unopened intemodes at the top of the plant—that is, remote 
from the injected intemodes, showing white glistening nodules in tissues which de¬ 
veloped mostly after the injection. One of these sections is from a branch and the 
others are from the main axis. Between the uppermost injected intemode and 
these nodules two and three nodes intervened. Photographed on September 11, 1916. 
Petiole natural size. Figures 2 to 5, X 2. 
6.—Normal pith from Plate 24, figure 1. It joins on (in direction of the upper 
arrow) to right side of Plate 24, figure 2. Arrow at bottom indicates the longer axis of 
the stem. X160. 
67908°—17-6 
