•211 



" But to'my great satisfaction I made sure that it was possible to 

 extract the latex of the ' Ecanda ' (although mixed with the sap of 

 the roots) with great ease by means of simply crushing the roots. 

 To extract the latex proceed as follows : — After having washed the 

 roots well, cut them into several pieces at a right angle to their 

 greatest diameter and subject them to a slight pressure in a 

 copying press. When the liquid ceases to flow raise the top of the 

 press, turn the pulp and subject it anew to slight pressure. Repeat 

 these operations as long as the liquid comes out yellowish and 

 without streaks of white, that is to the point when the latex is 

 completely extracted and only root sap continues to flow. 



" To obtain this result it is necessary to extract from the roots, 

 on the average, 77*7 per cent, (of: the weight) of the liquor ; hence 

 the latex is much diluted (1*5 per cent, of the liquid extracted 

 from the roots should on the average be pure latex). Having 

 found a practical process for extracting the latex, I tried now to 

 determine ihe best method for coagulation. 



" I obtained good coagulation with alcohol or brandy whenever 

 the latex was not very much diluted. This process is evidently 

 . not economical as the coagulating agents are dear. . . . 



"Acetic acid, sulphate of aluminium and potassium, phenol 

 and chlorate of sodium do not act on the latex diluted with root 

 6ap. . . . Other coagulating agents I was not able to try. . . . 

 It is, however, probable that coagulation of the latex of 4 Ecanda ' 

 may be obtained with other agents, even when it is diluted with 

 root sap. 



" The process of skimming leaves much to be desired, since, in my 

 experiments, I have never succeeded in extracting by this method 

 more than half of the caoutchouc contained in the latex . . . 



i 



"I also studied the effect of heat on the liquid obtained by 

 pressing the roots of the ' Ecanda.' 



" If the liquid is subjected direct to the action of fire, a 

 skin forms on the surface, like that on boiled milk, con- 

 sisting of caoutchouc. If this skin is removed in the measure 

 as it forms, its production ceases after some time, and when at 

 length the liquid is completely evaporated, a copious yellow and 

 viscous residue is left. 



" By substituting a hot bath for direct fire and proceeding in the 

 manner just described, there also remains a yellow and viscous 

 residue, but it is less copious. In this way I obtained a greater 

 percentage of caoutchouc which was of greater elasticity than 

 that produced by coagulating direct over fire. 



"Thus by using heat as the coagulating agent I always obtained 

 beside the caoutchouc a more or less copious residue of a yellow 

 and viscous substance. Now, it is well known, that generally 

 caoutchouc, if subjected to temperatures above 35° a, gradually 

 loses its elasticity, and turns viscous, until at 170 to 180 t . 

 it is converted into a thick liquid much resembling molas es. 

 Therefore, it might be supposed that the residue mentioned above 

 also consisted principally of resinified caoutchouc. 



32336 



A 2 



