Fruit Brevities. 427 



not know if the trouble is communicable from tree to tree, but 

 the fact that great numbers of trees sometimes become infested 

 in the nursery rows, seems to show that it may spread from tree 

 to tree. However, one of the most distinguished German authori- 

 ties upon plant diseases, Sorauer, thinks that these galls are sim- 

 ply abnormal deposits of woody tissue consequent upon the 

 abrupt bending or injury of the roots when the trees are planted. 

 A portion of his account is here translated (Sorauer, " Haudbuch 

 der Pflanzenkrankheiten," 1886, p. 737): 



" These swellings have been seen by me mostly upon apples 

 and pears. They appear generally at the crown of the roots of 

 young trees, the enlargements having the size of hazel nuts or 

 walnuts. In older specimens they may attain the size of one's 

 fist. Their appearance upon the younger nursery stock is gener- 

 ally limited to the crown, but not unfrequently they are found 

 lying deeper in the earth, or even upon slender one-year-old roots. 

 In older trees they are much less frequent. The swellings have 

 been found only upon those roots which lie near the surface of 

 the soil. In those cases in which the galls have attained con- 

 siderable size, a decreased growth of the branches of the trees 

 may be noticed. Apparently, the gall absorbs so large a part of 

 the nourishing material that the branches suffer. An unfavor- 

 able effect of these galls upon the roots appears to be a decreased 

 development of small fibrous roots. This is especially noticeable 

 in older trees. 



" The color of the gall is similar in its younger stages to that 

 of the sound root. Later, a darker color appears, in consequence 

 of a deposit of dead material which forms the bark of the gall. 

 If one examines the galls which are produced upon the smaller 

 roots, it will be seen that they are generally located upon one 

 side* of the root body; that they have a softer tissue than the 

 root, but that their color within is perfectly normal; and that 

 they also possess an equal amount of starch. The large galls are 

 composed of hemispherical growths which are superseded upon 

 each other in such a manner that the surface has a very irregular 

 granular and warty appearance. In the springtime the more 



