THE PEACH. 107 



serious disease to which this tree is subject. 

 Careful microscopic observations have shown 

 that in all cases of diseased trees different forms 

 of fungous growth enter first on the surface of 

 the trunk or branches, and penetrate throughout 

 the woody tissues. The tree becomes of a sickly 

 yellow color, the foliage is much reduced in 

 size, the fruit ripens prematurely, and is insipid 

 in flavor. The debatable question is, whether 

 these fungi are the cause of disease, or only a 

 consequence of the enfeebled condition of the 

 tree. Working upon the last supposition, ex- 

 periments have been tried at the Massachusetts 

 Agricultural College to impart vigor to the tree, 

 by a liberal supply of the deficient element of 

 potash. It is stated by Professor Goessman 

 that chronic cases of "yellows " have been re- 

 covered, after a treatment of three or four years, 

 by the use of muriate of potash applied to the 

 roots. It certainly appears probable that in this 

 case, as in the analogous case of pear fire-blight, 

 and in cases of white mildews upon the grape 

 and gooseberry, the parasitic fungous growth is 

 invited by some enfeebled condition of the plant. 

 Instances of recovery, under treatment, plainly 

 point in this direction. 



If, instead of either of the formulas given 

 above as complete fertilizers, muriate of potash 



