4 



and wood. Both continuation of decay and the effort of the 

 trunk to repair the injury go on together, but it is generally a 

 losing battle. The dead region spreads in spite of the efforts 

 made to produce a callus, covering an enlarging elliptical area 

 on which the little branch shoot appears in the middle as a sort 

 of centre about which circle the lines representing the different 

 stages in the piocess. As time proceeds, the rest of the trunk 

 receives the normal additions of wood and bark, while the dead 

 parls become more and more an element of weakness." 



Unfortunately no specimens of oak showing this disease are 

 preserved in the State College collections, but the occurrence of 

 the Strumella disease in the vicinity of State College at the 

 present time lends added support to the descriptive evidence that 

 Buckhout was certainly dealing with the trouble described in 

 the following pages. It seems strange however, that a disease 

 recognized fifteen years ago should continue its ravages and es- 

 cape further study until the present time. 



Although our knowledge concerning this disease is still very 

 imperfect, sufficient data have been accumulated to justify us in 

 presenting a short account. The main object at the present time 

 is to call attention to the importance of the disease and describe 

 its characters in sufficient detail to enable foresters and path- 

 ologists to recognize it. 



SYMPTOMS AND EFFECTS. 



There is a rather remarkable parallelism between this new dis- 

 ease and the well-known chestnut tree blight as far as general 

 symptoms and effects are concerned. 



Young infections of the Strumella disease on smooth-barked 

 trunks can be easily recognized by the presence of yellowish 

 or yellowish-brown patches, slightly raised, and standing out in 

 marked contrast to the normal bark which is darker in color. 

 The area invaded by the fungus may be fairly regular in out- 

 line, but it is very frequently irregular in outline, the latter 

 showing what may be designated- as the amoeboid type of in- 

 fection (fig. 1). The most noticeable external difference between 

 young lesions of the chestnut blight (Endothia), and those of 



