Gossip Meeting “My latest microscopical acquisition”

Saturday 8th January 2022

The first meeting of 2022 was held on-line via Zoom and drew a good crowd of 44 members and visitors, including several from outside the UK.

Quekett members can watch a video of the meeting.

As usual with this theme there was an eclectic range of topics ranging from micro-manipulators to novel uses for Covid-19 lateral flow test devices.

Robert Ratford presented a fabric roll of instruments which he had bought for handling small items, samples and specimens.

blackhead removal kit

Robert’s inexpensive specimen manipulation kit

He was particularly interested in transferring cladocerans for examination, and the loops, tweezers and probes were ideal.

The kits are priced from £2.99 to £4.99 on eBay and, remarkably, are marketed as “blackhead and spot removal kits”, but this shouldn’t put off prospective buyers as they have proved good for Robert’s purposes.

Gordon Brown presented his Zeiss KM microscope, which is not especially common and was only produced for a short time before being discontinued by Zeiss due to poor sales.

Zeiss KM Gordon Brown’s Zeiss KM microscope

Originally intended for use in pathology laboratories where rapid turnover of specimens is needed, the KM has knob on the side that when turned rotates the nosepiece and changes the objective, and  also operates a ‘zoom’-type condenser of variable focal length in which both area of field illuminated and illuminating aperture are varied together, so no readjustment is required.  Only the brightness and aperture diaphragm need adjustment.

Zeiss KM side view

Zeiss KM – side view showing the objective changing knob

Changing slides is facilitated by a slide holder that has a tapered lead-in and automatic clipping.  There’s also a folding carrying handle in the top, which makes it ideal for taking to meetings.

Zeiss KM top view

Zeiss KM – top view showing carrying handle

Optically the microscope is very good, but there is no option for a trinocular head and it also lacks a coarse focus, although the objectives are almost perfectly parfocal.  If you can find one in good condition with a set of the black Zeiss objectives it may be worth buying as a go-to meeting instrument, but do check the stage carefully as they have a tendency to self destruct!

Gordon Brown also presented a new ring light which is less obtrusive than most available. It is produced as usual in China and sold on Aliexpress (https://www.aliexpress.com/item/1005001549422303.html?spm=a2g0o.9042311.0.0.1f754c4d7FyO5h) for £12.50 including VAT and postage.  This unit is very thin and is powered by a 2A USB plug (not supplied) with a touch-sensitive switch and dimmer.

ring-light

The internal diameter is a maximum of 58mm but it fits the DF Plan objective on Gordon’s Olympus SZH stereo exactly and looks like it is original equipment.  A very worthwhile improvement and recommended, just don’t forget you’ll have to buy a USB/mains adapter of 2A to operate it properly.

Les Franchi has found a new use for the now-ubiquitous Covid-19 lateral flow test kits as an everyday item as an aid  in slide mounting.

lateral flow kit

Lateral flow testing kit

The sample tube and the snap-off handle of the swab  are part of the kit.  Dispensing appropriate drops of LOCA from the commercial tube is somewhat hit and miss for quantity and placement on the slide, too much fluid often emerges, meaning a messy clean-up once a coverslip has been positioned over the specimen.
This squeezable tube (right) will hold 1.5cc of fluid, enough for a number of slides, or kept in the dark for  for another day.  Using these tubes gives a controlled amount of mountant from the nozzle, even for sucking back any large excess.  The plastic swab stick is handy for positioning the coverslip and applying gentle pressure where needed.

Lisa Ashby has recently been arranging the Member’s Auction and as a result has been speaking to a number of members for the first time; one of these was Colin Lamb.  They had been speaking about Ernie Ives and Colin offered to send her a Dr Carpenter’s test slide that Ernie had made.

ives and carpenter's slides

Ernie Ives’ test slide and Colin Lamb’s selection

Not only did he send the slide but he also sent four of his own mounts, referred to in his covering letter as “ a few of my old rubbish”.  As these have arrived on the day of the meeting she has not had the opportunity to look at these in detail but they are clearly far from rubbish and she is very much looking forward to spending some time with them.