PLATE 63 
1. —Same as Plate 62 but photographed by transmitted light to show the opaque 
' centers of the intumescences due to death of tissues and the chlorophyll-free trans¬ 
lucent borders which allowed the light to shine through readily, and therefore are 
white in the photograph. All the larger intumescences are ruptured. X3 1/2 
nearly. 
2. —Under surface of one of many leaves of a cauliflower plant exposed to vapor of 
primary ethylamin on December 5, and photographed December 14, slightly less than 
natural size. These swellings and bucklings of the parenchymatic tissue were not 
present when it was exposed and are possibly to be attributed to the exposure. The 
experiment was made by liberating the vapor from one-half gm. of primary ethylamin 
chlorid in 10 1/2 cubic feet of air space by adding 10 c. c. of a 15 per cent solution of 
sodium hydroxid. Eighteen leaves on the exposed plant showed the phenomenon, 
the domes of the curvatures being directed toward the lower surface of the leaf. These 
parts are thicker than the normal parts of the leaf and their palisade tissue has given 
place to round-celled parenchyma (PI. 64, fig. 2). In a repetition of the experiment 
5 leaves showed the disease on one plant and 12 on another. 
