A DISEASE IN TURNIPS CAUSED BY BACTERIA 3S 



subject, and his unaffected enthusiasm for his science could not 

 fail to arouse his students' sympathy and interest. 



Looking back now, where but a little while ago we thought only 

 of looking forward, it behoves us not to estimate the measure of 

 his work without remembering the difficulties against which he had 

 to contend, and towards all of which he bore himself cheerfully and 

 manfully. And writing these few lines as a tribute to his memory, 

 my thoughts dwell not more upon his scientific work than on his 

 personal character, for it was beyond common measure pure and 

 lovable. 



D. W. T. 



A DISEASE IN TURNIPS CAUSED BY BACTERIA. 



By W. Carruthers, F.R.S., and A. Lorrain Smith. 



[This memoir was prepared for the Royal Agricultural Society. 

 By permission of the Society it appears here contemporaneously 

 with its publication in the Society's Journal, but with a few technical 

 additions for scientific readers. — Ed.] 



For some years we have been acquainted with an injury to 

 turnips, the cause of which we were unable to discover. The 

 injured turnips had the crown of young leaves destroyed, and a 

 cavity scooped out of the turnip occupied the top immediately 

 below where the leaves had grown. The cavity was empty; its 

 wall was of a dark brown colour, and the tissues were protected 

 by the development of a corky layer. There was no indication of 

 injury in the turnip beyond the wall of the empty cavity. The 

 first specimen was received seven years ago, and some years later 

 other specimens were obtained ; they threw no hght on the cause 

 of the injury. It seemed probable that the injury was due to 

 bacteria, but we did not discover any evidence of their presence. 



At the beginning of August, 1900, a number of badly diseased 

 swede turnips were sent from the valley of the Nibb, in Yorkshire, 

 in order that the nature and cause of the injury might be deter- 

 mined. In the worst cases the young leaves had disappeared from 

 the crown or were rotting away; the outer older leaves also 

 showed signs of wilting, their stalks were decaying at the base, and 

 a number of lateral buds were shooting up from the axils of these 

 older leaves. As a rule, the outer skin of the turnip was intact, 

 In some instances the top was as if scooped out, and the depression 

 hned by a whitish slimy substance. In others the injury had 

 further penetrated through the turnip to the base, and the whole 

 centre was a mass of rotten pulp. Even in the plants less seriously 

 affected, it was evident from the condition of the younger leaves 

 that they were being cut off from their connection with the root. 

 Some of the turnips had wounds at the side, through which the 

 bacteria gained access, forming starting-points of disease in addition 

 to the injury at the top of the bulb. In the specimen figured an 

 older cavity was found agreeing with the injury already observed. 

 Journal of Botany.— Vol. 39. [Jan. 1901.] d 



