The Microscope - Volume 63, Third Quarter 2015

IN THIS ISSUE:

On the cover
Fluorescence photomicrograph by Katie M. White of Microtrace, LLC shows buccal (cheek) cells stained with DAPI under ultraviolet light excitation. White’s image was the overall winner of the Inter/Micro 2015 Photomicrography Competition. See Inter/Micro 2015 on page 99.

Editorial | Chemical Microscopy = Classical Microscopy = Truth

Gary J. Laughlin
The Microscope 63 (3), p ii
Excerpt: Anyone who has ever read The Microscope or used a microscope in any analytical way has probably considered the instrument’s long history or thought about what the future may hold for microscopy. Those of us who have practiced microscopy for some time can learn to appreciate the microscope’s origin, persistence and practicality. We also like to reflect on microscopists and their pursuit of the truth. “Even the best microscope becomes a boring toy in the hands of the inexperienced.” Those were the words of German botanist, microscopist and microchemist Julius von Sachs more than 140 years ago. He emphasized that the successful use of the microscope is impossible without proper training.

Inter/Micro 2015

Gary J. Laughlin
The Microscope 63 (3), pp 99 – 118
Excerpt: McCrone Research Institute’s 67th annual Inter/Micro microscopy conference was a pleasurable success this year, attended by leading microscopists and researchers from around the world. It was held on June 8 – 12 at McCrone’s lecture rooms and laboratories in Chicago. Participants heard in-depth research presentations by amateur, professional and graduate-student microscopists, who covered advancements in instrumentation, new techniques and practical applications in various fields of microscopy and microanalysis. Presentations focused on PLM, SEM, EDS, Raman microscopy, hot-stage and infrared microspectros-copy; microchemistry; forensic trace evidence and criminalistics; pharmaceutical sciences; materials analysis; environmental health; food analysis; and air quality.

Polarized Light Microscopy for Determining the Principal Refractive Indices of Components in Polished Thin Sections (Part 1 of 2)

Franz W. Nentwich
The Microscope 63 (3), pp 121 – 130
Abstract: In 1767, the Duc de Chaulnes determined the refractive index (RI) n of a glass plate with a compound microscope from the equation, Refractive Index ≈ Real Thickness/Apparent Thickness. This method was adapted by Sorby in 1877 to determine the principal RIs of mineral plates. For thin sections the method was hampered by the difficulty of identifying a section’s underside with transmitted light, but this surface can be identified easily with incident darkfield illumination. Another complicating factor, the effect of permanent coverslips can be avoided with uncovered polished thin sections. Transmitted circularly polarized and circularly analyzed light expedites the selection of suitably oriented anisotropic crystals, and guided by their interference figures, these crystals can be rotated into the orientations needed to measure principal RIs. The ω RI of uniaxial crystals can be determined from crystals in any random orientation, while the ε, α, β and γ indices can be determined with a narrow slit, the long axis of which is oriented perpendicular to the analyzer’s privileged direction. Accuracy is attained by calibration with a RI standard and by accurate measurements of axial translations of the microscope stage relative to the microscope tube.

Critical Focus | Leeuwenhoek Microscopes: Mystery and Mischief

Brian J. Ford
The Microscope 63 (3), pp 131 – 142
Excerpt: So, unknown Leeuwenhoek microscopes still exist? The remarkable revelation that three new examples have emerged has surprised many — none more than me. I was astonished in 1981, when I discovered that Leeuwenhoek’s original specimens still lay hidden among his letters in London, yet nobody expected more of his microscopes to emerge. These are dramatic developments, and the curious tales of double-dealing that surround them are remarkable. Each Leeuwenhoek microscope is unique and tells a fascinating tale. They are valuable, too; the single example that was recently sold on the open market cost half a million dollars.

Afterimage | Lavender Attack