1911.1 



PUBLIC DOCUMENT — No. 31. 



155 



Table 1. 



Series A. — Showing Eesults of Inociilalion of Heallhy Young Grawlh 

 ivilh Tissues from Malformed Plunls. 



Series B. — Filtered Juice used for Inoculation. 



The appearance of the leaves of " mosaic " f)lants is usually 

 different from that of diseased shoots in the case under discus- 

 sion. In mosaic these are flattened areas of cells which are 

 lighter in color than the normal areas, and which are also 

 smaller in size, growing more slowly than the normal cells, this 

 causing a general unevenness or distortion of the leaf. 



On the other hand, in the trouhle under discussion, where 

 ahnormality occurs, the tissue of the leaf itself is not so much 

 distorted as the vessels and veins. These are usually curved 

 more or less, and thus distort the leaf. The leaf, also, is always 

 of a healthy dark-green color, and shows no division of cohn* 

 into light and dark areas. Plate II. (Figs. 4 and 5) shows a 

 ty])ical mosaic leaf and some from affected sprout growth. 



The cause of mosaic is not exactly known, but it has been 

 produced repeatedly by severe ]U'uuing in the case of tomatoes, 



