484 CASUALTIES OF VEGETABLES. CHAP. XII. 



they at last united and formed a cicatrice, which was 

 a new bark, not indeed covering the whole wound 

 uniformly, for some parts of it still remained un- 

 covered, and not altogether like the other bark. 



Hence, says Du Hamel, it is proved that the 

 , wood can produce bark. But the legitimacy of this 

 conclusion is, I think, somewhat questionable. For 

 in the first place the liber was not wholly stripped off 

 and in the second place the cicatrice was not com- 

 plete; and in the third place the bark was not 

 perfect. 



If the decortication is total, the tree dies. Of 

 sixty trees which Du Hamel barked in the spring, 

 no one survived the experiments above three or 

 four years, though many of them generated a por- 

 tion both of wood and bark, originating at the sum- 

 mit, and descending sometimes to the extent of a 

 foot.* 



SECTION II. 



Diseases. 



DISEASES are corrupt affections of the vegetable 

 body, arising^from a vitiated state of its juices, and 

 tending to injure the habitual health either of the 

 whole or part. The diseases that occur the most 

 frequently among vegetables are the following: 

 Blight, smut, mildew, honey-dew, dropsy, flux of 



* Phys, des Arb. liv. v. chap. ii. 



