1894. NOTES AND COMMENTS. 171 



In a tj'pically affected plant the leaves are smaller than is 

 generally the case, and are transformed in such a manner as to 

 become strikingly like those of the stinging-nettle. The edges of the 

 leaves turn upwards ; the fibro-vascular bundles in them are increased 

 slightly in thickness, and stand out well from the under surface of 

 the leaf. 



Closer examination shows destruction of the soft tissue in 

 immediate contact with the fibro-vascular bundles ; the parts become 

 thin and yellow, and much resemble the thin spots produced by the 

 action of sulphur dioxide gas on the leaf. 



The internodes of the plant are short and the main stem and 

 branches taper more rapidly than in healthy plants. In practically 

 all cases the bine or stem, after climbing a short distance up the pole, 

 loses it power of twining and topples over ; when not tied up the 

 whole stem becomes slack, slides down its support, and the plant lies 

 in a heap on the ground. 



So far the experiments, which are being carried out on the 

 Bettring estate of Messrs. E. A. White & Co., Paddock Wood, 

 point to the circulation within the plant of a poison which brings 

 about curling of the leaf, stoppage of growth of the fibro-vascular 

 tissue, and loss of turgor of the cells in the leaf near the ribs, with 

 resulting yellow patches there. 



The leaves on the main stem nearest the ground are affected 

 first, and then follow those at the nodes above in regular succession. 

 The branches in the axils of these show the same regular sequence of 

 diseased leaves, the lower branches being affected first. The cause 

 is undoubtedly connected with the root, and Professor Percival finds 

 in the cortex of man}' diseased specimens, close up to the bast, 

 considerable numbers of the nematode Tylenchus devastatrix, Kiihn, 

 usually known as an eel- worm. 



Before any completely satisfactory cause can be established or 

 remedy suggested, much work is necessary. At a later date we hope 

 to be able to give an extensive communication from Professor 

 Percival dealing with this interesting and important investigation. 



The Indian Geological Survey. 



The usefulness of the Geological Survey of India appears to be 

 fully recognised by the practical men of the Dependency. Thus, we 

 read in the Records, vol. xxvii., p. 65, that, in his inspection of the 

 Bengal collieries, Mr. Grundy, the Inspector of Mines, has "ex- 

 perienced very earnest co-operation on the part of the agents and 

 managers of the mines." On the other hand the Survey is not blind 

 to the advantages it may itself gain by friendly co-operation with the 

 practical men. The maps of many large coal-fields that were made some 

 twenty and thirty years ago, on the largest scale available at that 

 time, are now found to be insufficient. It is suggested therefore 



