September i, 1907.] 



THE INDIA RUBBER WORLD 



2>17 



Fruits That Yield Rubber. 



IN view of the successes attained recently in systematic rubber 

 culture, and of the still large yield of forest rubber, it may 

 appear to some to be an extreme view to suggest that trees 

 and giant creepers may not always serve as the world's main 

 dependence for its rubber supply. Not that any rubber trees 

 now standing are in danger of being neglected; they will be 

 drained of the last drop of latex, even if this involves the de- 

 struction of the trees. But what about the future? Does it 

 give promise of the development of new sources of rubber, 

 through the evolution of plants now considered as minor and 

 even insigniticant rubber producers ? Already the study has been 

 begun of "quick crops" for the production of rubber, as succulent 

 stalks or tubeis. And students of comparative agriculture cite 

 in this connection the instance of the sugar supply, which was 

 derived first from trees, then from juicy stalks, and now most 

 largely from the beet root. 



An ideal rubber plant, if such could be found, would be one 

 from which the product could be gained in the shape of fruits, 

 without injuring the tree, as grapes or apples are gathered. 

 In the light of recent experiments in vegetable evolution, this 

 field seems well worth investigating, because there are known 

 already several species of rubber bearing fruits whose yield is 

 considerable and appears to be capable of a rapid development. 



There are bananas and grapes which yield a small amount of 

 rubber. The banana rubber process was patented in 1896, but 

 the yield is not large enough to compete with the food qualities 

 of the fruit, though the rubber might perhaps be exploited as a 

 by product in making banana flour. The latex is 95.7 per cent, 

 water and 3.9 per cent, rubber, and it is easily coagulated by 

 boiling. 



A much better known instance of fruit rubber is found in the 

 Mexican chicle (Achras sapota), which yields the chewing gum 

 of commerce. The chicle gum usually contains from 35 to 55 

 per cent, of resin, and about 18 per cent, of rubber. This product 

 is obtained by tapping the tree, but the best gum comes from 

 the fruit. This fruit is about the size of an apple or osage 

 orange, and, like the osage orange, is quite full of milk. ITiis 

 milk is coagulated by gentle boiling. When freshly clotted, the 

 gum forms a tough, white, aromatic, and rather elastic mass, 

 which later becomes friable. 



Tabfrtiacmotilaiiii OidiiuH ^niuim (Rose; is another Central 

 American and .Mexican fruit, which yields what may be termed 

 a blend of rubber and gutta-percha. It is an Afocynacea, called 

 "cojon de puerco" by the natives. The tree seems to be found 

 in West Africa, also, and it has been cultivated in Kamerun, 

 though the size of the fruit is disappointing, rabcntacinontana 

 is a shrub or dwarf tree, often used as shade for coffee. It 

 bears fruit at four years old. The latex is coagulated with lemon 

 juice or brine, making a yellowish curd which is kneaded like 

 gutta-percha. 



A recently discovered and still unclassified Mexican rubber 

 fruit is the "papelillo," which grows abundantly in the states of 

 Guanajuato and Michoacan. Samples of the rubber are now 

 being tested in the United States and Europe. 



An interesting fruit tree comes from Sao Thome, Africa, from 

 a private experimental garden at Porto AUegre. The tree itself 

 does not yield rubber, but the fruit, which is as large as an 

 orange, is said to be rich in latex. The gum shows 23.8 per cent 

 of substance insoluble in hot acetone, which would almost fit it 

 for immediate use as a gutta. 



Africa furnishes numerous rubber and gutta fruits. A Zan- 

 zibar fruit is said to yield considerable gutta, but details are 

 wanting. Marsdcnia verrucosa, a Madagascar vine, called "bo- 

 kabc" by the natives, appears to be a promising rubber source. 

 The fruits ripen in May or June, and 200 of them yield a quart 

 of milk, on an average. The fruits are merely sliced and allowed 

 to drip. Better extraction methods might secure a larger yield 

 of latex. 



Cryptostegia Madagascariensis, or "lombiry," contains milk both 

 in the fruit and the stem. The fruits are smaller, 1000 being 

 needed to get a quart of rubber latex, which is curdled by adding 

 tamarind juice and boiling. Landolphia spherocarpa, or "ariabo," 

 another Madagascar vine, has rubber bearing fruits, but the vine 

 itself is more important as a rubber source. 



Karite gum or "gutta-shea," has been known to the trade foi 

 30 or 40 years, and yet the reports from it are conflicting. It 

 is commonly ascribed to the fruit of Bassia Parkii, or Butyro- 

 spermiim Parkii (Kotschy), a West African Sopotacca. It was 

 for many years believed, on the authority of Dr. Meckel, that 

 the gutta came from the trunk, while the butler was derived 



Rubber Yielding Mistletoe. 



[Strntanthus svriiigifoHus (Mart.), or "tina macho," growing upon its ho.^t. 

 Native to Brazil, Venezuela and the Guianas. The large berry variety, 

 and the most important of the rubber mistletoe species.} 



.\xoTHER View of the S.n.me Plant. 

 (Showing the method of fastening to a bough.] 



