PLATE 51 
1, 2.—Free-hand unstained sections (water mounts) from old cauliflower intu¬ 
mescences caused by vapor of ammonia. The proliferation, which is much more 
compact than the normal tissue, is entirely or almost entirely from the loose paren¬ 
chyma below the palisade tissue. The latter contains chloroplasts, but the intu¬ 
mescence does not. The vascular system (fig. 1 VB) appears to have been very little 
disturbed. Same series as Plate 50, figure 2, but much older. Exposed on August 
28, 1916, sectioned and photographed on September 30. Most of the intumescences 
had shriveled by the end of the eighth week—that is, the stimulus was exhausted. 
X160. 
