a2 LIFE OF A TREE, 
that is, not dependent on changes taking place 
in the tissues of plants, hasten their decay and 
premature close of life. Thus a plant may be 
erowing where it cannot get enough air, or enough 
light, or it may be consumed with thirst; or 
there may be some substances actually deadly 
to it in the soil; or other plants, such as weeds, 
may crowd around it, and suffocate it by their 
close-entangled roots. The wild beast may trample 
it down, the tempest may uproot it, the severity 
of the Winter may freeze it through, the heat 
of Summer may scorch it, and finally, man him- 
self, whether in the character of the woodman, 
reaper, or gardener, may put an end to its exist- 
ence for the accommodation of his own purposes, 
or for the gratification of his tastes. 
Beside all these messengers of death to the 
vegetable kingdom, it is a very interesting and 
singular fact that plants are subject, just as man 
and animals, to the attacks of disease. To us 
who have suffered so severely in consequence of 
the recent visitation of Providence,—the potato 
disease, —this subject is peculiarly interesting ; 
but it is impossible to spare room to enter into 
it fully in these pages. There is a disease liable 
