372 



GENERAL PLANT PATHOLOGY 



The number of 



were cultivated at an abnormally high temperature, 

 nuclei rarely exceeded three. 



Multinucleate cells occur in crown gall which are perhaps compar- 

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

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



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

 numerous giant cells are seen, the nuclei of which have begun to degenerate; 6, irreg- 

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

 C, a single multinucleate giant cell. {AfUr Tischler in Kiister, Pathologischc Pflanzen- 

 analomie, 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 maUgnant and those 

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

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



