a teacher's knowledge of plant pathology. 
197 
be cured by enriching the soil if the roots, stems and leaves are in 
good condition. Mild cases of poisoning can be cured, but severe 
cases invariably prove fatal. Wounds that have been neglected 
are incurable, but if treated properly when first formed, they 
may generally be made to heal quickly and effectively. The loss 
of necessary organs is not necessarily irreparable. New leaves 
will sometimes appear after they have been destroyed by insects or 
other causes: roots will often push out to take the place of those 
which were cut off, and even flowers which have been destroyed 
may be replaced by a later set if the tree is in vigorous condition. 
On the other hand diseases due to fungi are generally incurable 
in any proper sense. An internal leaf fungus cannot be eradi¬ 
cated when once it is inside of the leaf, and so a fruit-rot or a 
stem-rot cannot be remedied. In such cases prevention is all that 
can be accomplished. We can prevent the fungus from getting 
into the leaf, stem or fruit, but when once it is inside it is safe 
from any sprays or other remedial measures which we can em¬ 
ploy against it. 
Avoid Quacks. 
The last thing to which attention should be called in con¬ 
nection with this matter of plant diseases is that here as else¬ 
where there are quacks to be avoided. There are all sorts of 
patent medicines advertised for curing all sorts of plant diseases. 
Now. these things are just like the patent medicines which fill 
so many yards of shelving in the drug stores in every town,— 
they are made to sell, and to bring money into the pockets of 
the makers of the medicines. My advice to every plant grower is 
to refuse absolutely to buy any of these advertised remedies and 
so-called “ plant invigorators.” When you are sorely tempted 
to buy a cure-all for your tree troubles write to the botanists in 
the Agricultural Experiment Station of your State, and they will 
give you the best advice available, and not charge anything for 
it, either. 
