’ PLATO 52 
1, 2.—Vertical sections of two ammonia-vapor intumescences on a cauliflower leaf 
showing an enormous hypertrophy of cells and no hyperplasia. The sections are from 
stained material which was fixed nine days after exposure to the vapor. Intumes¬ 
cences developed wholly from the cells of the loose parenchyma—that is, palisade 
tissue and vessels not involved. The volume of the largest cells in the tumor is a hun¬ 
dred times that of the normal cells out of which they have developed. These sec¬ 
tions may be contrasted with those on Plates 51 and 57 to 61 which show hyperplasia. 
X160. 
