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EXT to coffee and sugar, crude rubber is the largest of the tropical imports of the United States. It is the only one of these three for which we are entirely dependent on foreign countries. The value of the crude rubber that we import every year, 55,000,000 pounds, reaches about $30,000,000, but none of it comes from Porto Rico or the Philippines. Over one-half of the total is imported direct from Brazil, while considerable quantities come from the United Kingdom, presumably the products of her colonies, and from Belgium, chiefly the product of the Congo Free State.

It occurred to the Department of Agriculture, while pondering what new industries might be found for Porto Rico and the Philippines to improve conditions on the islands, that rubber trees might be grown profitably on them. An agent of the Department, Mr O. F. Cook, was therefore sent to Central America and Mexico, where millions of dollars are invested in rubber plantations, to study rubber culture and to report on the advisability of starting similar plantations in our new island possessions. Mr Cook spent several months at the different rubber plantations, and his preliminary report has been published by the Department.

It is yet too soon to state definitely whether rubber trees can be successfully grown in Porto Rico, but the prospects seem favorable for growing the Castilla rubber tree, as the southwestern part of the island is dry and hot. It should be noted that crude rubber may come from three different kinds of rubber trees, each requiring different climate and soil. There is the Para rubber tree (Hevea), which thrives in the wet valley of the Amazon, but which will not grow in a dry climate; the Assam rubber

(Ficus elastica) of Java, also needing a humid atmosphere; and the Castilla rubber tree of Central America and Mexico, which prospers best where it is dry and hot and will not grow in swamps or wet soil. Mr Cook recommends that experiments be begun by planting a number of Castilla rubber trees in Porto Rico and the Philippines, but he warns the American public against investing large sums in starting rubber plantations until it has been proved that the rubber tree will grow successfully on these islands.

The accompanying illustrations, for the use of which the NATIONAL GEOGRAPHIC MAGAZINE is indebted to Mr Cook, give interesting information about the rubber tree and the native Mexican method of tapping it for its milk.*

It would seem to be a very simple matter to improve on the rude gashes made by the machete of the rubber gatherer, but this has not proved to be easy. The rubber milk is not the sap of the tree and can not be drawn out by boring holes in the trunk, as is done with the sugar maple. The milk is not in the tissues of the tree, but is contained in delicate tubes running lengthwise in the inner layers of the bark, and to secure milk in any quantity it is necessary to open many of these tubes by wounding the bark. The rubber is formed in floating globules inside the tubes and can not pass through their walls, so that even a suction apparatus would not bring it out unless the tubes were cut.

The method by which the natives of Soconusco, Mexico, have been accustomed to extract the milk is shown in

*Consult The Culture of the Central American Rubber Tree." By O. F. Cook. U. S. Department of Agriculture: Bureau of Plant Industry-Bulletin 49.

picture No. 2. The ulero makes with his machete diagonal lines of gashes, extending nearly around the tree, like the letter V, the point being downward. The milk flows down these channels to one side of the tree, whence it is led down to a cavity hollowed in the ground and lined with large, tough leaves. These are dexterously lifted up, and the milk is poured out into a calabash or other vessel and carried away to be coagulated. The diagonal channels are from two to three feet apart, and those of each successive tapping are inserted between the older scars. The milk will all run out of the tree in about an hour.

A Castilla tree 5 feet in diameter will yield when first cut about 20 gallons of milk, making 50 pounds of rubber. The tree may be cut again after the lapse of a few months. That the trees at La Zacualpa shown in picture No. I have been able to survive so much of this barbarous treatment and are still vigorous and heavily laden with fruit seems to indicate great tenacity of life, and yet even this rough handling represents an improvement upon the former custom of cutting the trees down entirely or hewing steps in them for the ulero to climb up. Instead of the forked stick used as a ladder at La Zacualpa, the large forest trees are ascended for 30 feet or more by means of ropes, vines, climbing irons, and steps cut in the trunk.

The studies which the Department of Agriculture is making in regard to starting rubber plantations on American soil are specially important in view of the disappearance at no distant day of the rubber forests of Brazil and Africa, whence nearly nine-tenths of the supply of rubber now comes. The world is almost entirely dependent on savages, or on natives too barbarous to be called civilized, to get the rubber out of the forests. They, tempted by the high price which rubber brings, swarm into the rubber forests and chop the trees down to save time in collecting the milk.

Mr K. K. Kennedy, U. S. consul at Para, Brazil, has recently sent to the Bureau of Statistics of the Department of Commerce and Labor the startling reports of two expeditions which have been examining conditions in the rubber country. Captain Gerdeau, after exploring, investigating, and canvassing the territory of the upper Amazon and its tributaries in the richest rubber belt in South America for more than a year, advises him that the rubber gatherers are cutting down the forests with amazing rapidity and improvidence, far beyond what his previous information had led him to expect. He expresses grave doubts if the supply can be kept up unless stringent measures to protect the rubber forests be immediately taken.

Robert Blair Ewart was a member of an American exploring expedition which started inland from Lima, Peru, crossed the Andes, and then descended the tributaries of the Amazon and the great river to Para. Mr Ewart described to Consul Kennedy the rubber-hunting in eastern Peru, along the Ucayali River, a tributary of the Amazon:

"The Ucayali is a magnificent stream, as large as the Mississippi, and traverses one of the finest rubber districts in South America. In all this great territory. there is but one man who is producing fine rubber. All the rest are caucho hunters. These latter are the bane of the country, and have done incalculable damage in the past few years. They do not bleed the trees in the regular way, but cut them down and extract the gum by the wholesale. Thus every year enormous forests are destroyed, and each year the supply grows less and less and the rubber gatherers are compelled to go farther back from the rivers. This makes the production of rubber more difficult, dangerous, and expensive each year, and it is only a question of time when this immense and most important rubber-producing terri*Daily Consular Reports, October 21, 1903 (No. 1780).