GUTTA CULTIVATION. 49 



was, of course, nothing but that well knowu solvent of gutta 

 percha. Their processes appear to be covered by Dr. Thomas 

 Cattell's patent for " treating and purifying gutta percha," 

 dated 1859, and by various other published accounts of extract- 

 ing and purifying processes. However these gentlemen have, I 

 believe, proved that excellent quality gutta may be extracted 

 from the leaves and twigs, as I proved in 1883 that similar 

 good gum could be extracted from the bark. 



M. Rigole's process is to place the crushed leaves and 

 twigs in an iron cylinder, and dissolve out the gutta by passing 

 a fluid through it. The solvent used is bisvilphide of carbon, 

 which is put into a vaporizer and the vapour rising from it is 

 conducted by a pipe to the top of the iron cyhuder, where it is 

 condensed in a refrigerator and allowed to run through the 

 crushed leaves and back into the boiler. This process is con- 

 tinued until the leaves are exhausted of gutta. Then a jet 

 of steam is turned through the cylinder and the vaporizor, with 

 the effect of carrying all the bisulphide of carbon with it into a 

 condensing tank and leaving the gutta as a solid mass in the 

 vaporizor. The drawing accompanying the specification does 

 not shew a practicable apparatus, in fact it is merely a crude 

 diagram, but an apparatus on this system coidd easily be devised. 

 In this climate artificial cold would have to be employed to 

 condense the vajDour of bisulj^hide of carbon, as it boils at a 

 temperature of 46° centigrade, and gives off vapour very freely 

 at much lower temperatures. Presumably a working apparatus 

 has been constructed as preparations are complete for the 

 treatment of large quantities of leaf ; but no description of it 

 would appear to have been published. 



It seems quite possible that by taking advantage of the 

 properties of this licpiid solvent, the application of artificial heat 

 to the vaporizor, the introdviction of the steam at the end of the 

 process, the condensing water tank, and the rifrigerators could 

 all be done away with. If this could be accomplished, and I 

 cannot see any reason why it should not, the extraction would be 

 much simplified, the process becoming continuous instead of 

 intermittent, the solvent would throughout the process be at 

 a lower temperature than the air, and the gutta would therefore 

 run no chance of deterioration wiiile it, together with the spent 

 leaves, would be delivered free from water at the end of the 

 operation, and finally, and by no means the least important point, 

 the chances of an explosion would be very much reduced. This 

 suggested new process would be so different, both as regards 

 apparatus and principle, to that of M. Rigole that it would not 

 infringe his patent in any way. 



