A Method of Preparing Sections of Fossil Plants contained in Coal Balls or in other Types of Petrifaction
Abstract
THE method described in this letter was devised in collaboration with Dr. R. G. Koopmans of Utrecht. A flat surface must first of all be cut or ground on the coal ball or other petrified mass parallel to the planes in which the sections are required: this surface is ground smooth, but a fine polish is not necessary. The surface is then immersed for a definite length of time in an etching solution of hydrochloric acid, the optimum concentration being found by trial. The acid dissolves away a film of the carbonate of which the mass is largely composed, and the plant substance contained in the film is left behind, standing in relief above the surface. The surface is washed carefully and dried. A solution or fluid, which on drying or hardening forms a tough film, is then poured over the surface and allowed to dry or harden. Several solutions have been used for this purpose; the best as regards consistency is the trade preparation `Durofix,' but other solutions containing cellulose compounds may be used. When quite hard this film of cellulose-compound may be peeled off, as it has considerable tensile strength. The plant substance which was left in relief by the etching process is embedded in the film and is detached with it from the surface of the petrifaction. The film is then washed, first in the acid and then in water, dried, cleared, and finally mounted in Canada balsam between a slide and coverslip. The surface of the petrified mass is gently rubbed down on fine carborundum paper and is then ready for the removal of another section.
- Publication:
-
Nature
- Pub Date:
- October 1928
- DOI:
- 10.1038/122571a0
- Bibcode:
- 1928Natur.122..571W