The preparation & mounting of microscopic objects — A Reader’s Guide

A Handbook Built from Borrowed Authority

Davies’s preface makes clear that his book is a compilation. He writes that “much information … has been already published; but mostly as supplementary chapters only,” and that he has made “numerous quotations” from other authors, acknowledging sources wherever possible. This reliance on external authority shapes the reader’s experience: the text is less a single voice than a curated anthology of techniques. Davies occasionally inserts his own preference—for example, he thinks it “better to leave it in strong acid until all the substance … is removed” when preparing siliceous skeletons—but he presents alternatives without dogmatism. The beginner is thus guided through a landscape of competing methods, not a single prescribed path.

Precision in the Details: Starch, Raphides, and Silica Skeletons

The excerpts reveal Davies’s attention to specific manipulations. For starch grains, he instructs the reader to wash the grains “through two or three waters” and notes that they show “a dark cross whose lines meet at the point where it was attached to the plant, called the hilum” when viewed with polarized light. For mounting, he advises applying a tiny amount of balsam diluted with turpentine to make the grains cling to the slide, reducing air bubbles. Raphides require only thorough washing before mounting in balsam. The most elaborate procedure is for siliceous skeletons: the plant material is boiled in strong nitric acid until effervescence ceases, then either washed and burned on thin glass or left in acid until all organic matter is removed. Davies warns that the latter method “will take a length of time, varying according to the mass.”

The Polariscope as a Guiding Light

Throughout the excerpts, the polariscope emerges as a key tool for revealing hidden structures. Davies describes starch grains showing a dark cross, raphides giving “beautiful colours,” and siliceous skeletons from grasses and horsetails providing “splendid object[s] for the polariscope.” He also notes that leaf scales, when mounted in balsam, “present brilliant starlike and other forms” under polarized light. The polariscope is not merely an accessory but a central motivation for many of the mounting techniques. Davies encourages the student to be “always on the lookout” for new specimens of scales, which are “much more abundant than was formerly supposed.” This emphasis on a single optical method gives the handbook a focused practical thread.

A Beginner’s Path Through Competing Recipes

Davies’s method of presenting multiple approaches—sometimes with a mild recommendation, sometimes without—places a burden on the beginner to choose. For siliceous skeletons, he describes two routes: one involving burning on thin glass, the other prolonged acid digestion. He states his own preference but does not dismiss the alternative. Similarly, for mounting leaf scales, he suggests applying a thin layer of diluted balsam to the slide beforehand to prevent the scales from being displaced by the wave of balsam when the cover glass is lowered. These small tips, scattered among the citations, reward careful reading. The novice who works through the text sequentially will accumulate a repertoire of tricks and precautions, even if the overall structure is that of a reference manual rather than a step-by-step tutorial.

Davies’s handbook is best approached as a collection of recipes and observations to be consulted rather than read straight through. The excerpts show a writer who values precision and acknowledges the contributions of others, but who also trusts his own experience. Readers new to microscopy may find the density of alternative methods challenging; experienced practitioners will appreciate the comparative detail. The polariscope emerges as a unifying theme, linking starch, raphides, siliceous skeletons, and leaf scales into a coherent set of preparations worth mastering.

That rainy afternoon, Davies’s meticulous instructions for mounting starches felt like a quiet meditation on patience—each step a small act of faith in unseen structure. Later, idly wondering how such preparation reveals life’s hidden order, I found myself turning to The Principles of Biology, Volume 2 (of 2) — Context and Discussion, where the same careful attention seemed to bloom into something broader, almost without my noticing.