372 



GENERAL PLANT PATHOLOGY 



were cultivated at an abnormally high temperature. The number of 

 nuclei rarely exceeded three. 



Multinucleate cells occur in crown gall which are perhaps compar- 

 able to the giant tells of the animal histologist. Cancer specialists have 

 divided these into two groups, viz., foreign-body giant cells in which the 



Fig. 148.- — Cross-section of a part of a root gall of Circaa luteliana in old stage, 

 numerous giant cells are seen, the nuclei of which have begun to degenerate; b, irreg- 

 ularly branched nuclei out of the giant cells dividing by amitosia within anuceoli; 

 C, a single multinucleate giant cell. {After Tischler in Kuster, Pathologische Pflanzen- 

 anatomie, 1903: 128.) 



stimulus is some introduced foreign substance, and genuine ones in 

 which no foreign bodies are visible. There is probably no real distinc- 

 tion other than that those occupied by parasites are malignant and those 

 induced by non-Hving granules are harmless. The cells in question in 

 crown gall are not very large, but they contain several nuclei (Fig. 



