(rums, Resins, 



216 



[Sept. 1906. 



latex tubes of Para trees arise by the perforation and decomposition of ordinary cells 

 of the bark (cortex) ; secondly, that the processes involved require an interval of time 

 for their completion which the constitution of the plant determines ; and lastly that 

 in tapping operations we are dealing with a series of channels which have no very 

 vital association with other parts of the bark. 



FEEDING THE LATEX TUBES : THE CONVERSION OP MANURE INTO RUBBER. 



There is one very interesting section here which reveals a condition of 

 considerable importance, in so far that it shows contact, but not open communication 

 of a milk tube with what is called a "vessel" of the young wood; the vessels 

 of the wood are mainly concerned in storing the water which has been absorbed 

 by the roots, and, if direct communication could be proved between a vessel 

 and a latex tube, we should be very near solving the great problem of how to feed 

 the milk tubes and make them more productive. (Demonstration). I think you 

 will all see how, so long as the vessels holding the water, and some of the Colombo 

 manure absorbed by the roots, are in contact and not in open communication with 

 the milk tube, the direct feeding of the latter in twenty-four hours' notice will be 

 very difficult and perhaps impossible. Bat if direct communication can be shown to 

 exist our knowledge of the functions of the latex and our power to influence its 

 accumulation may perhaps be appreciably increased. It is a point observed long 

 before my arrival in Ceylon, but I have not yet been able to follow it up ; it is not 

 generally known, and is well worth studying by anyone who can find the time to 

 work it out. Perhaps the first effect of very soluble manures on the composition of 

 the latex will throw some light on the subject? Anyhow, I think records of the 

 first and subsequent effect of manures on the latex should be recorded by all who 

 have the opportunity to make such observations ; the man who discovers the condi- 

 tions under which the latex tubes may become more completely charged with the 

 required ingredients will gain for himself a substantial reward. 



LATEX TUBES DRYING UP. 



Sufficient has been said to give you an idea of the nature of the origin of the 

 latex tubes in the bark or cortex and their associations with other parts of the tree. 

 It only remains to point out that in a well-grown tree the latex tubes run more or less 

 vertically, up and down the stem, and are irregularly connected by means of channels 

 running horizontally or in an oblique direction. If you examine the growing 

 parts of the stem you will find that the bark, or— as it is better termed— the cortex, 

 is formed from within outwards ; new cells are continually being formed which push 

 the older ones outwards. Now all these cells, at some time or other, are liable to 

 undergo decomposition and to assist in the production of well-defined tubes which 

 become filled with latex ; it is obvious that the material now constituting part of the 

 dead dry bark of your untapped trees was originally part of the cortex and at one 

 time probably contained latex, but is now dry and all signs of latex in it are gone for 

 ever. It is quite correct that this occurs originally, but it is as well to point out that 

 much of the dry bark of old stems or even renewed bark arises in another way— from 

 the cork cambium— and never contains any signs of milk tubes or latex. The fear of 

 the milk tubes drying up and peeling away and the anxiety for preventing loss in 

 any way are, however, no excuse for extracting the latex at too early an age. 



MOST LATEX INNERMOST. 



The bark of mature trees usually possesses a good proportion Of milk tubes, 

 most of which occur in the innermost part of the cortex, very near the cambium. It 

 is a pity the higher proportion of laticiferous tubes are so near the vital cambium^ 

 but with the advent of two pricking knives already brought forward by Ceylon 

 planters, the extraction of the latex from the treacherous and deeply-hidden area 



