52 



fungi, states that, for twelve months, Badhamia utricularis was 

 under daily notice, and that during this time there was no 

 break in the " constant rythmk: motion " of the organism. 

 Mr. Lister says that his investigations " offered no clue to the 

 mystery of the rythmic streaming motion, any more than they 

 explain why, at uncertain intervals of hours or days, the 

 plasmodium will rouse up, without provocation, from a 

 quiescent condition and flow over a glass shade, and then 

 return to its former state. We may suppose that it is search- 

 ing for food, but this is far from accounting for the unity of 

 action that appears to pervade this creature."* 



Though De Bary classifies Plasmodiophora brassicce among 

 the " doubtful mycetozoa," it is clear, at least, that it possesses 

 the "rythmic streaming," and most of the other attributes 

 common to the undoubted forms of this group of myxomycetes. 



Woronin was the first to discover that Plasmodiophora 

 brassicce is the cause of Club Root. He sowed cabbage seed in 

 soil in which were clubbed roots, with the result that the 

 plants from these seeds were almost invariably clubbed. 

 Cabbage plants from seed sown in soil free from clubbed roots, 

 and watered with sterilized water, were free from disease. 

 Many similar experiments, made by other persons, have 

 confirmed Woronin's experiences. 



REMEDIES AND MODES OF PREVENTION. 



From the nature of this infection it would appear that 

 remedial measures can hardly be of efficacy, as the slime 

 fungus invades the plants in their early stages. It would, 

 however, be desirable to apply a good dressing of lime when the 

 first symptoms of the infection are noticed, and work it into 

 the soil with horse hoes, and round the plants with hand hoes. 



Lime has been proved frequently to be a preventive of Club 

 root. Mr. Clare Sewell Read, in his " Farming of Oxfordshire,"f 

 written in 1854, points o.ut that, on the Green Sand in that 

 county, " lime is principally applied as a dressing to cure ' Club 

 root' in turnips. Some land requires 10 quarters of lime every 

 8 or 12 years before roots can be grown with any certainty. 

 Not only do turnips suffer, but even mustard and rape. While 

 hot, the lime is applied to the land ; a man follows the plough, 

 sowing the lime from a seed-cot at the bottom of the furrow, 

 which is covered over by the next turn of the plough to the 

 depth of three or four inches. If applied in this manner it is 

 a certain cure for this disease, and has never been known to 

 fail. Stone lime is much more powerful than that made from 

 chalk. If chalk lime is used the dressing must be repeated 

 every four, or at the most, eight years." 



* Notes on the Plasmodium of Badhamia utricularis and Brefeldia maxima, by 

 Arthur Lister, Annals of Botany, vol, ii., No. T., June 1888. 



f Jouinal of the Royal Agricultural Society of England, vol. xv., ser. 1, p. 195. 



