PLATE 28 



A. — 491X, inoculated artificially with unfiltered juices from mosaic plant February 

 22 to March 22, 1919. Note mottled leaves on the two new shoots at apex of plant. 

 Green Mountain variety. 49iy, control, untreated plant from half of same tuber as 

 491X. Greenhouse, Washington, D. C, 1919. 



B. — 473y, inoculated in same way as 49 ix, but with juices from healthy plant. 

 48sy, also inoculated with juices from healthy plant. Greenhouse, Washington, D. C. 

 122502°— 19 3 



