Economic Botany: A Textbook of Useful Plants and Plant Products

By Albert F. Hill | Go to book overview

CHAPTER VI
RUBBER AND OTHER LATEX PRODUCTS

RUBBER

Rubber is obtained from the milky juice, or latex, of various erect or climbing woody plants of the tropics or subtropics. The majority of the rubber plants belong to the Moraceae,Euphorbiaceae, or Apocynaceae. Although well over fifty species are available as sources, only a few have been important commercially and at the present time Hevea brasiliensis stands preeminent. Wild trees were formerly the only source of rubber, but now cultivated Hevea trees, the so-called plantation rubber, furnish about 98 per cent of the supply. Rubber is the most recent of the major crops of the world. The industry is little more than 100 years old, and cultivation has been carried on only 60 years or so. In view of this, the increase in the production of plantation rubber from 800 long tons in 1900 to 305,000 tons in 1920 and 1,395,000 in 1940 must be considered as one of the greatest triumphs in modern agriculture. This great development of the rubber-growing industry has not been without its drawbacks, however. Overproduction has seriously affected the industry financially in recent years, and many attempts have been made at some sort of regulation. The British and Dutch, in particular, have tried to restrict production and exert other methods of control in Malaya, Java, Sumatra, and other plantation rubber centers within their empires. The recent successful development of synthetic substitutes for rubber, after many years of experimentation, may further tend to jeopardize the natural rubber industry. However, while these substitutes are superior for some purposes, such as the conduction of oil, natural rubber is still preferred for tires, which utilize three-quarters of the rubber output.

Latex occurs in special cells or in a series of special vessels which permeate the bark, leaves, and other soft parts of the tree. Usually only the latex from the lower part of the trunk is of importance commercially. Latex is a gummy white liquid full of minute globules. It is a varying mixture of water, hydrocarbons, resins, oils, proteins, acids, salts, sugar, and caoutchoue, the substance used as the source of rubber. The significance of latex to the plant is obscure. It is of some value in the healing of wounds, and it may serve for protection, nutrition, the transport of materials or as a fluid reservoir.

The properties of rubber have long been known. The primitive

-135-

Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this page

Cited page

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited page

Bookmark this page
Economic Botany: A Textbook of Useful Plants and Plant Products
Table of contents

Table of contents

Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this book
  • Bookmarks
  • Highlights & Notes
  • Citations
/ 560

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.