1] Finger and Toe, and Wart Disease 37 
become yellowish and the plant makes very little 
growth. A diseased plant possesses, instead of the 
normal development of fibrous root, a swollen nodular 
mass. The fancied resemblance of this mass to fingers 
and toes gives the disease its popular name. Exami- 
nation of a thin section of one of these nodules mounted 
in water shows large cells scattered amongst cells of 
a, Spores. 6, Plasmodium. 
Fig. 13. A section of a turnip root very highly magnified showing the 
giant cells caused by Plasmodiophora brassicae. Some of the giant 
cells contain “plasmodium” and other spores. (Magnified.) 
ordinary size. The contents of the larger ones are 
darker in colour and very different from those of an 
ordinary normal root cell. The high power of the 
microscope shows that the contents consist either of a 
frothy granular mass or of a very large number of tiny 
spheres (see Fig. 13). These are the spores of the 
Finger and Toe fungus. They are very small and 
measure only gj55 of an inch in diameter. 
