LETTER OF SUBMITTAL.

DEPARTMENT OF COMMERCE,

BUREAU OF FOREIGN AND DOMESTIC COMMERCE,

Washington, February 27, 1918.

SIR: Submitted herewith is a monograph on tanning materials in Latin America, prepared by Dr. Thomas H. Norton while he was a commercial agent of this bureau. The paper was submitted to the Second Pan American Scientific Congress, and was published in Volume VIII of the proceedings of the congress. As the edition of the proceedings is limited and its distribution confined mainly to libraries and Government offices, it has been deemed advisable to issue the paper in separate form, to make it more readily available. to tanners and others interested in the leather industry.

The monograph presents a comprehensive survey of the tanninbearing plants and trees in South and Central America and Mexico, and reveals the resources of these countries, thus far only slightly exploited, for meeting the increasing demands for tanning materials. Statistics of the Argentine quebracho industry have been brought down to the latest possible date.

Respectfully,

To Hon. WILLIAM C. REDFIELD,

B. S. CUTLER,
Chief of Bureau.

4

Secretary of Commerce.

TANNING MATERIALS OF LATIN AMERICA.

INTRODUCTION.

Throughout the more densely populated regions of the earth the available supply of vegetable material for use in tanning is steadily diminishing.

The importance of a more perfect and exact knowledge of the varied substances which contain tannin is now generally recognized. In not a few tropical and subtropical lands a more or less complete "census" of the trees and shrubs belonging to this category is now being taken.

Few parts of our globe possess such a variety of tannin-bearing plants and trees as those included under the designation "Latin America."

It is the purpose of this study to enumerate and describe as completely as possible the known occurrence of such sources of tannin in the countries in question and to show the extent to which they are already utilized or are easily susceptible of exploitation.

It is highly probable that in many cases the real economic value of these American tannin yielders has not been fully appreciated. I was led to this conclusion by the appearance during 1913 in a prominent organ of the leather industry of the following list:

It will be noticed at once from the above list with what painstaking care the sources of tannin in the British Colonial Empire have been studied.

CLASSIFICATION OF TANNING MATERIALS.

Tanning materials, in the broadest meaning of the term, include all substances capable of changing the skins of animals into leather. By this change the skin ceases to be liable to decay under ordinary conditions, becomes more or less soft and pliable, and is, as a rule, impermeable to water.