32 PRESENT DISEASE IN THE TOTATOE. 



on the premature decay of the plant. In the first place, 

 the plant perishes before the tuber is properly ripened, and 

 thus the tuber will be injured ; in the second, the fruit 

 may perish before it has arrived at its perfect state, and 

 hence the seeds may be incapable of renewing the species. 



(121.) In the progress of the malady the potatoe plant 

 is observed to give off a most offensive odor. This is fre- 

 quently an early symptom of the existence of the malady, 

 and it will continue till the haulms of the entire field be 

 destroyed. 



(122.) Before the stalk perishes, if the plant be atten- 

 tively observed at the dawn of day, the under side of the 

 leaf will be found to be perfectly dry : this is an undoubt- 

 ed symptom of the diminished vitality of the plant. In 

 the healthy vigorous plant the under surface of the leaves 

 will be covered with a copious dew, doubtless the exhala- 

 tion of the plant. 



(123.) In observing a large field we find that it is not 

 every plant which perishes ; but that one here and there 

 is damaged, but not destroyed, and that this plant conti- 

 nues its vigorous growth for some time' longer. 



(124.) Upon examining these vigorous plants they will 

 generally be found to possess two sets of under-ground stems. 

 Above the lower set the stalk may be found to be dead, and a 

 separation to be thus effected between them and the leaf; 

 but above the upper and younger set, which have grown 

 at a later period, after the plant has been earthed up, the 

 stalk may still be sound, and thus a continuity preserved 

 between the leaf and the root. 



(125.) It does not, however, preserve its integrity long ; 

 the stem, hitherto apparently sound, generally becomes 

 affected, the leaves become dry, and the whole plant dies. 



