1911. 



PUBLIC DOCUMENT — No. 31. 



155 



Table 1. 



Series A. — Showing Results of Inoculation of Healthy Young Grawth 

 with Tissues from Malformed Plants. 



Series B. — Filtered Juice used for Inoculation. 



The appearance of the leaves of " mosaic " plants 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 troul)le under discussion, where 

 fibuormality 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 color 

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

 typical mosaic loaf and some from affected sprout growth. 



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

 produced re])eatedly by severe ])niiuiig in the case of tomatoes, 



