(38) 



bottle or biscuit, has formed upon the paddle, which is then 

 removed and allowed to dry and season. By this method, 

 not only is the rubber coagulated, but the creosote of the 

 smoke acts as an antiseptic and prevents putrefaction of 

 the albumin in the rubber. The mass thus formed contains 

 much water, which gradually dries out as the rubber is 

 kept. As the process continues the color gradually changes 

 from milky-white to yellow, brown, and black, the central 

 portion long retaining its white color. By modern im- 

 provements on the above method, the milk is coagulated 

 by the addition of various substances and the water then 

 squeezed out of it by pressure. Occasionally, the resins 

 and other foreign matter are removed from the milk by 

 chemical processes, leaving the rubber. Still other pro- 

 cesses are described below. 



Rubber trees are now largely grown in plantations, 

 especially in Java. 



THE SPURGE FAMILY (Eupkorbiaceae) 



Nos. 844-906 illustrate Para rubber and articles made from it. This is the 

 best quality of rubber known and is obtained from various species of the genus 

 Hevea. These are large trees, native of the entire Amazon valley and extending 

 somewhat into adjacent regions. 

 844. Branch bearing leaves and fruits of Hevea brasiliensis Muell. Arg. Grown 



in Java and presented by William Fussani, 1919. 

 845-847. Hevea seeds.— The seeds of a species of Hevea packed in charcoal, by 



a special process, the only way in which their vitality can be preserved 



for any considerable length of time. Presented by the India Rubber World. 

 848. 16 Rubber pick.— A pick used for puncturing the bark to cause the flow of the 



rubber milk. 



849. The same with a long handle. 



850. Another specimen of the same, presented by John Lane Beck, of New York 



City. 



851. The rubber milk as it comes from the tree. 



852. "White" rubber milk.— This milk, after remaining several years in a bottle, 



has naturally coagulated and formed itself into rubber. Acquired on the 

 Upper Rio Negro by Weiss & Schmidt. 



853. "Red" variety of same. Same source and donors. 



854. Tichella. — Cups used for catching the milk as it flows from the tree. 



855. The same, presented by John Lane Beck. 



16 Unless otherwise specified, were presented by Nos. 848-871 Carlos Manuel 

 Asensi, of the Rio Madeira, Brazil. 



