CH. Vni.] THE DISEASES OF TUlSTS. 263 



to counterbalance the transpkation of the leaves, and 

 the diseased is veiy discernible amongst its healthy 

 companions, by its pallid hue and flagging foliage. 

 The disease now makes rapid progress, the swelling 

 continues to increase, for the vessels of the alburnum 

 and the bark continue to afford their juices faster 

 than they can be conveyed away ; moisture and air 

 are admitted to the interior of the excrescence 

 through the perforation made by the maggot; the 

 wounded vessels ulcerate: putrefaction super^'enes, 

 and death concludes the stinted existence of the 

 miserable plant. The tumom' usually attains the 

 size of a large hen's egg ; has a rugged, ichorous, 

 and even mouldy surface, smelling strong and offen- 

 sively. The fibrous roots, besides being. generally 

 thickened, are distorted and monstrous from swell- 

 ings, that appear throughout their length, and 

 which appai'ently arise from an effort of nature to 

 form receptacles for the sap, deprived as it is of its 

 natui-al spissation in the leaves. These swellings do 

 not seem to arise immediately from the attacks of the 

 weevil ; for I have never observed them containmg 

 its larva. 



Mr. Marshall very correctly describes the form 

 which this disease assumes when it attacks the 

 turnip. It is a large excrescence appearing below 

 the bulb ; growing to the size of both hands, and as 

 soon as the hard weather sets in, or it is by its own 



