PLATE 64 
Plasmodiophora brassicae . 
A. —A longitudinal section through a young cabbage stem. Infection has taken 
place at two points on the stem and the swellings are about to fuse together, The 
cambium between the two swellings is already infected. X 12. 
B. —A longitudinal section through a cabbage stem 11 days after inoculation of 
a single small spot on the stem. The infected tissues are beginning to respond to the 
parasite. Only the outer portions of the cortex are infected at this time. X 12. 
