1889.] 



PUBLIC DOCUMENT — No. 4. 



54; 



Fig. 1. Two potatoes, " Beauty of Hebron,'' from Station 23] a ts, badly 

 affected by " scab," illustrating the visual form of the disease. 

 Fi-om photograiihs. Five-sixths natural size. 



rig. ^. 



Fig. 2. Section taken at right angles to the surface of a healthy potato 

 tuber, showing its normal sti'ucture. 

 sk. The " skin " of the tuber, of tabular cork-cells. 

 I. A lenticel, filled v/ith rounded cork-cells. 

 p. The pai-euchymatous tissue, which forms the bulk of the 



tubers, containing starch-grains, st. 

 Original. Magnified one hundred diameters. 



