64 CENTRAL AMERICAN RUBBER TREE. 



tree, like the letter V. the point being downward. A cut like this is made about 

 every 3 feet all the way up the trunk. The milk will all run out of the tree in about 

 an hour after it is cut, and it is collected into a large tin bottle made flat on one side 

 and furnished with straps to fasten onto a man's back. A decoction is made from a 

 liana {Calonydion speciosum), and this, on being added to the milk in the proportion 

 of 1 pint to the gallon, coagulates it to rubber, which is made into round, flat cakes. 

 A large tree, 5 feet in diameter, will yield, when first cut, about 20 gallons of milk, each 

 gallon of which makes 2^ pounds of rubber. I was told that the tree recovers from 

 the wounds and may be cut again after the lapse of a few months; but several I saw 

 were killed through the large harlequin beetle (Acrocinus longimanus) laying its eggs 

 in the cuts, and the grubs that are hatched boring great holes all through the trunk. 

 When these grubs are at work you can hear their rasping by standing at the bottom 

 of the tree, and the wood dust thrown out of their burrows accumulates in heaps on 

 the ground below. " 



AGE AT WHICH PLANTED TREES MAY BE TAPPED. 



The earliest age at which Castilla trees may be tapped with safety 

 and advantage has been stated all the way from four to twelve years, 

 while from eight to ten years is the conservative estimate. At the 

 same time it must be admitted that little in the way of positive 

 knowledge exists on this point, and careful experiments may be nec- 

 essary to determine whether, for example, the taking of half a pound 

 of rubber from each tree in the sixth year will retard growth so as 

 to diminish the yield of succeeding years. As the trees approach 

 maturity and have occupied most of the available space, as much may 

 be taken as will not weaken the tree and shorten its life. 



The inferior quality of the rubber obtained from young trees also 

 lessens the inducement for tapping them. It has been known for 

 several } T ears that the rubber and gutta-percha obtained from young 

 plants or from the leaves and twigs of the trees is different from that 

 yielded by a trunk of mature age, in that a smaller or larger percent- 

 age of rubber is replaced by nonelastic. brittle, or sticky substances 

 commonly referred to as " resins. r Dr. C. O. Weber has recently 

 published the following results of analyses of samples of rubber from 

 trees varying in ao-e from two to eio-ht years: 6 



.Resins in rubber from trees — Per cent. 



2 years old 1 42. 33 



3 years old 35. 02 



4 years old 26. 47 



5 years old 18. 18 



7 years old 11. 59 



8 years old 7. 21 



The same writer also gives a table showing the varying- amount of 

 resin in samples from different parts of the same tree: 





a The Naturalist in Nicaragua, Thomas Belt, F. G. S., pp. 33-34. The liana called 

 by Belt Calonyclion speciosum is generally called Ipomoea bona-nox. 

 & Tropical Agriculturist, 22:444, January, 1903. 





