110 Experiment Station Report. 



Although the disease was in its first stage, the results show 

 a marked difference in regard to the relative proportion of 

 the mineral constituents of the healthy fruit, as compared 

 with that from the diseased tree or the prematurely ripened 

 fruit. These results seemed to prove the correctness of my 

 views regarding the first cause of the disease. 



Feeling, however, not satisfied with an explanation based 

 on a presumed analogy of circumstances, I invited Prof. 

 Penhallow, in the fall of 1880, to join me in the investiga- 

 tion by making some microscopic observations for the pur- 

 pose of establishing, if possible, more clearly the relation of 

 the fungus to the disease. 



The questions proposed to him may be summed up as 

 follows : — 



1. Is there any abnormal accumulation of starch in the 

 diseased wood, as compared with a healthy wood? 2. Does 

 the wood of the restored tree regain again the general ap- 

 pearance of that of the healthy tree? 3. What becomes of 

 the funsjus in case of a diseased tree beiuff restored to 

 health? These questions were to be answered by an exami- 

 nation of a lot of branches taken from healthy, diseased and 

 to-health-restored trees. The three samples of branches of 

 the peach trees, from which the previously stated specimens 

 for microscopic observation had been selected, were each 

 carefully examined, and the ashes subjected to a careful 

 analysis. The branches were secured in the presence of 

 Prof. Penhallow, Nov. 11, 1881. 



Their analysis was carried on by me, and repeated under 

 my immediate supervision by an efficient assistant. 



/. Analysis of the ashes obtained from the branches of a diseased Early 

 Gran ford Peach tree. 



Ferric oxide, . 

 Calcium oxide, 

 Magnesium oxide. 

 Potassium oxide, . 

 Phosplioric acid, . 



1.44590 

 64.22920 

 10.28270 

 15.67516 



8.36690 



II. Analysis of the ashes obtained from the branches of a peach tree 

 which had been affected in previous years by the yellows, and had 

 been restored again to health in consequence of the treatment de- 

 scribed in preceding pages. 



