52 THE PHILOSOPHY 



peculiar to the flowers and fruit, and often occafion barren- 

 nefs for a feafon ; and fometimes this fterility continues dur- 

 ing the exiftence of the plant. Others afTault the vifcera, or 

 internal organs, and gave rife to obftrudlions, tumors, and a 

 gradual refolution and corruption of the whole fabrick. 

 Many of the difeafes of plants are produced by the infe^l 

 tribes. Their wounds and depredations are not confined to 

 particular parts, but extend from the root to the ftem, branch- 

 es, leaves, flowers, and fruit. Infe£ts not only injure the 

 fubftance of plants, but, by feeding on their juices, deprive 

 them of a part of their nourifliment, and occafion various dif- 

 eafes or changes in their organization. Other difeafes of 

 plants derive their origin from change of climate, from miaf- 

 mata or noxious vapours in the atmofphere, and from im- 

 proper culture. When wounded by external injuries, vege- 

 tables dlfcharge their blood in copious ftreams. If the wound 

 be not mortal, the fibres on all fides gradually flioot out and 

 clofe the fra(^ure by a callous fubfi:ance. 



From this general enumeration, it is obvious, that the 

 difeafes of plants are not only fimilar to thofe of animals, 

 but proceed from the fame caufes. In both kingdoms, fome 

 difeafes are only partial or fuperficial, and are cured either 

 by Nature, or by the afliftance of art. Others are mortal, 

 and fucceeded by a total putrefa(Slion or decompofition of 

 the individual. 



But, though plants fhould efcape the numberlefs difeafes 

 which daily threaten them, they have no defence againfl the 

 flower approaches of old age, and its unavoidable confequence, 

 death. In progrefs of time, the vefTels gradually harden 

 and lofe their tone. The juices no longer move with equal 

 celerity as in youth. They are not abforbed with the fame 

 precifion. They at laft flagnate and corrupt. This corrup- 

 tion is foon communicated to the vefTels in which the juices 

 are contained, and produces a total cefTation of all the vital 

 fun6lions. 



