DISCOVERY 



279 



into thinking that the boughs were being floated by 

 the current. 



And where was his camera ? That, let me tell you, 

 was under his sheltering contrivance fixed to an 

 anchored floating base. His first filming effort was a 

 failure, for the camera's clicking frightened the bird 

 away. 



But one futUe attempt did not daunt this enterprising 

 young man, for he ne.xt procured another camera and 

 attached it to the same floating base. Day after day 

 he waited for the regular appearance of his victim, 

 when he turned the handle of the second camera, 

 which was without any film. This went on for seven 

 weeks, at the end of which time the kingfisher had 

 learnt to pay no attention to the working of the 

 motion-picture machine. 



All he had to show for his untiring efforts was a strip 

 of film two hundred feet in length. Snappy, it is 

 true, but it was run off the screen in two minutes. 



Some British birds are cliff-dwellers, and this adds 

 an element of danger to the work of the motion-picture 

 photographer. He usually works with a tripodless 

 camera, and has himself lowered down a tall cliff on 

 a rope. The extra powerful lenses are handy for ap- 

 proaching the birds at a distance unawares. 



Equally tedious to film are those birds that favour 

 the ground for buUding their nests, for, apart from 

 the fact that considerable skill is required to focus the 

 apparatus in the right-angle, it is hard to " snap " 

 the feathered creatures off their guard. 



Rubber Tree Diseases 



Rubber shareholders are, as a rule, more concerned 

 with the purely commercial aspect of the industry than 

 with the scientific side, but for those who care for such 

 things there is a wide field of interest opened up by some 

 of the technical features of the industry. How little 

 is really known about the growth and origin of rubber 

 is surprising, and knowledge of the real fimctions of the 

 rubber tree and the production of latex is still in a very 

 undeveloped condition. 



Among the numerous questions that arise in connec- 

 tion with the origins of latex and other fundamental 

 problems of the industry may be asked, " WTiat is the 

 particular function of the latex in the life of the tree ? " 

 The only answer is that nobody knows. That the 

 rubber tree is related to theterpene family and that 

 the production of latex has a family relation with 

 other resinous substances is known, but apart from 

 this the real function of the secretion is still unknown. 



Yet it is obviously essential that, in the best interests 

 of rubber cultivation, this primary function should be 

 understood. The need for increased research work in 

 an industry which now employs some £80,000,000 of 

 capital is very apparent. Planters are very apt to 

 work by rule-of-thumb methods. How many planters 

 have any real knowledge of the intrinsic differences 

 between good and bad yielding strains of trees at the 

 date of planting ? Yet close research into the qualities 

 which differentiate the good yiclders from the bad, with 

 the possibilities of selection which could then be exer- 

 cised, might well have the effect of doubling the yields 

 from any given area. Not many people outside those 

 immediately interested know that the laticiferous tubes 

 in the cortex of the rubber tree are arranged diagonally, 

 so that the choice of the tapping cut from left to right, 

 or vice versa, may make a vast difference in the yield, 

 owing to the number of tubes intersected by the cut. 



\Yhen the number of diseases and enemies to which 

 rubber trees are subject are considered, the casual 

 observer is inclined to wonder how rubber trees manage 

 to survive at all. It is something like the study of a 

 medical treatise, from which the reader can easily 

 persuade himself that he has symptoms of almost every 

 known complaint. Fortunately, however, as in the 

 latter case, all diseases do not attack every tree or every 

 plantation at once. To-day Brown Bast easily takes 

 first place among the enemies of rubber plantations. 

 So far as the general public is concerned, this is practi- 

 cally a new disease, and it is instructive to note that no 

 reference to it is found even in the later treatises on the 

 subject. In point of fact, however, it has been known 

 for many years, but only recently has attention been 

 drawn to it to any considerable extent. In the old 

 days when plantations were closely planted, it was a 

 simple matter to eliminate altogether trees affected 

 with this fatal disease. With the wider planting now 

 generally practised, however, every tree counts for a 

 tree, and, as every rubber shareholder knows, the 

 question has recently assumed considerable pro- 

 minence. 



The first sign of brown bast is a big increase in the 

 latex peld of the tree affected, but this soon diminishes 

 and ultimately ceases altogether. The bark discolours 

 and hard burrs appear, and, if the disease is neglected, 

 the tree becomes useless. The disease is very prevalent 

 throughout the East, few estates having less than 5 per 

 cent, and some as high as 60 per cent, of their trees 

 affected. Curative methods, such as resting, liming, 

 and manuring, have been tried without success, and 

 the only remedy known so far is that of stripping the 

 bark from the portions attacked, after\vards shading 

 the cambium • until a new growth of bark has developed. 



' The cellular tissue which lies between the wood aad the 

 bark. 



