3 8o 



process of the formation of rubber may be summed up by saying 

 that it is a more or less catalytic action, or to be more accurate 

 surface action ; for the re-acting substances to be intimately con- 

 nected it is necessary that they be exposed to a large surface as is 

 found in the structure of a tree by means of this solution ; hence we 

 see that capacity for osmosis must exist between the laticiferous 

 system and the vessels, as was shown in the section referred to by 

 Mr. Wright. 



It is not easy to explain why it is that such a system exists. It 

 may be that the habitat of the plant and its environment may have 

 caused this change. The amount of water transpired by a tree 

 must partially depend upon the capacity of the atmosphere to take 

 up moisture, or the amount of water transpired will be lessened with 

 the increasing humidity of the atmosphere. In the Amazon Valley 

 where the plant flourishes, the atmosphere must be surcharged with 

 moisture so that a large quantity of water is thrown into the food 

 circulation of the tree, and this water maybe indirectly responsible, 

 as we have seen, for the abnormal polymerisation of the products of 

 assimilation, it is a bold venture to say so (as I know nothing of 

 it myself), because in that cause laticiferous trees must (not neces- 

 sarily in all cases) be indigenous in places of warmth and humidity. 

 Hence places with a larger rainfall and warmth (for without heat 

 the water will be incapable of being vaporised) must evidently 

 succeed better in the growing of the tree 



If also the soil be dry the transpiration current will be small, the 

 transpiration will also be small, and so the amount of the latex and 

 its percentage of rubber must be smaller than in the other case, and 

 the reverse will also be true. 



It was noticed by Mr. WRIGHT that an apparently dead tree may 

 yield latex, but we must here recall the recent work of SCHWALS- 

 BURGER, who showed that transpiration current may or rather really 

 does take place in a dead tree, so that though the activity of forma- 

 tion of the primary products of assimilation may fail it does not 

 follow as a logical sequence that the activity of formation of the 

 secondary polysen also fails, especially as polymerisation is a process 

 purely chemico-physical in some cases ; the water requisite is pre- 

 sent, being supplied by the osmosis taking place from the trans- 

 piration current, the re-acting surface is present, the products of 

 primary assimilation are also present, so that latex may form. 

 Lastly, from what has been said previously as regards tapping there 

 must be an optimum time when the formation of Caoutchouc is 

 finished, but before it has itself polymerised. As regards the age 

 for tapping it must be evident that when the plant is young the 

 processes of life are quickened so that the products formed must all 

 be subservient to the main requirement — viz., the growth of the 

 tree, so that even if latex is obtained it would be unwise to tap it. 



I have ventured to bring forward a bold idea, and out of justice 

 to myself, I must say it is only a plausible idea, and, as ideas are 

 often, may be all wrong, but one experiment which I cannot per- 



