394 PLAIN AND PLEASANT TALK 



bark is either dead and dry, or else at the same point the 

 bark will be puffed, softened, or sappy with thickened sap 

 — these two appearances indicating only difierent degrees 

 of the same blight. Wherever the bark is dead and dry, 

 the limb will flourish above it, make new wood, ripen its 

 fruit, but perish the ensuing winter. ^In the other case, as 

 soon as the circulation of the sap becomes active, the point 

 described shows signs of disease, the leaf turns to a darker 

 brown than is natural to its ordinary decay, being nearly 

 black, and the wood perishes. 



The disease, at first, blights the terminal portions of the 

 branch ; but the affection spreads gradually downward, 

 and sometimes affects the whole trunk. The time from the 

 first appearance of the blight to that in which any affected 

 part dies, is various ; sometimes two or three weeks — some- 

 times a day only ; and sometimes, but rarely, even a few 

 hours consummate the disease. * 



On dissecting the branch, the wood is of a dirty, broA^oi- 

 ish, yellow color ; the sap thick and unctuous, of a sour 

 disagreeable odor, like that of a fermented watermelon, on 

 the tops of potato vines after they have been frosted. In 

 still, moist days, where the blight is extensive in an orchard, 

 this odor fills the air, and is disagreeably perceptible at 

 some distance from the trees. 



Sometimes the bark bursts, the sap exudes, and runs 

 down, turning black ; and its acridity will destroy vegeta- 

 tion on Avhich it may drop, and shoots, at a distance from 

 the trunk, upon which the rain washes this ichor, will soon 

 perish. When we come to treat of the cause of this dis- 

 ease, it will be important to remember this malignancy of 

 the fluids. 



We are carefully to distinguish these ap[>carances, pecu- 

 liar to what I suppose ought to be called winter-blight, from 

 another and a summer-blight. In this last, the leaf is affected 

 at first in spots ; gradually the whole leaf turns russet 

 color and drops. Along the wood may be seen the hard- 



