PLATE 4 
A. —Green Mountain tubers kept in the same sack in a warm room from June i to 
August ii, 1919. The middle one had no net-necrosis and is withered, soft, and bearing 
normal sprouts. The others had net-necrosis and are smooth, firm, and bearing 
spindling sprouts. 
B. —Frost-necrosis of the net type produced by measured exposure to low tempera¬ 
ture. Thin slices of Green Mountain tuber cut off to increase the visibility of the 
injury. 
C. —Greenhouse-grown plant produced by a net-necrosis tuber (lot 1920-G of Table 
VI) and showing spindliness and slight leafroll. 
