Die Harze

An encyclopaedic survey of the botanical sources, production, chemistry and applications of natural resins. Resins and gum-resins of both terpenoid and non-terpenoid category are considered, including some entries on geologically-modified materials (bitumens, ambers or fossilized resins), plant and insect-derived waxes and (polysaccharide) gums. The chemistry and chemo-taxonomic elements of the text are thorough and most detailed, **for the times**. Hence, the chemical and botanical aspects are useful and enlightening from an historical point of view, but - of course - the former are mere shadows of the true, underlying chemistry of natural resins; one must bear in mind that sophisticated, chromatographic and spectrometric techniques were not available to separate the organic components into anything other than complex mixtures. The true worth of this historic and valuable text lies in its attempt to set down such information as was still extant on the sources, both geographical and botanical, the commercial classification and the traditional processing of naturally derived resinous materials.