PLATE 8 



A. — Tomato leaf showing the collapse of the palisade in the frozen areas. Note the 

 normal condition of the cells at the right of the trichome, in which no ice formation 

 occurred. 



B. — Crystals of calcium malo-phosphate in the injected areas of cabbage leaves pho- 

 tographed by polarized light. 



C. — Young tumor of cabbage leaf three days after freezing, showing large nuclei and 

 multinucleate cells. 



78774°— 18 4 



