Mounting medium question

[MsLichen]

I've pored through the beginner forum as well as searched on the main site, and couldn't find an answer.

My main interest is in making permanent slides of plant materials. It seems the favorite mounting medium is Euparal, but my searches for it in the USA have turned up nothing -- either the major suppliers have discontinued it or it is only available to professionals.

I'm at a loss -- what is the most low-risk (health-wise) mounting medium option you would recommend for a complete beginner in permanent slide making. Preferably not too pricey, so I can work on my technique without fear of bankruptcy

[Culicoides]

Euparal, and euparal essence, is available in the UK from Anglian Lepidopterists supplies; you would have to enquire about shipping to USA.
Good luck..

[Charles]

How about Canada Balsam? It's been used for ages for most permanent mounts
Another option is CytoSeal. I have never used it but it is inexpensive:
https://www.ebay.com/itm/NC-5988-CytoSe ... 1438.l2649

[clengman]

https://www.bioquipinc.com/options/eupa ... ng-medium/

Looks like they sell to the public?

[mrsonchus]

Hi, Brunel Microscopes in the UK have a range, aqueous (which I use for moss whole mounts), alcohol-based (Euparal) and 'Numount' resinous medium (which is my first-choice for permanent-mounts of sectioned & stained plant tissue slides)...

A screen-snip,

brunel mountants.JPG (44.15 KiB) Viewed 8609 times

Here's the link to their web-page

I use all three of these and can tell you that they are all very good indeed and fit for purpose.
Another option is of course glycerin (liquid) or glycerin-jelly (solid/set) which are both good for whole-mounts as ling as you seal them after about a month with a resin such as Numount or even nail-polish at a push....

Good luck, John B.

[MichaelG.]

... and 'Numount' resinous medium (which is my first-choice for permanent-mounts of sectioned & stained plant tissue slides)...

I am no expert in these matters, John ... but I would be wary of using Numount for anything you want to archive for posterity.
As a member of the Postal Microscopical Society, I have seen too many examples of crystallisation in Numount: It is perhaps feasible that people are thinning it with the wrong solvent, and degrading it ... but I have no evidence for, or against, that hypothesis.

If you have any mature examples of Numount slides, I would be very interested to know if you find any problem.

MichaelG.

[photomicro]

... and 'Numount' resinous medium (which is my first-choice for permanent-mounts of sectioned & stained plant tissue slides)...

I am no expert in these matters, John ... but I would be wary of using Numount for anything you want to archive for posterity.
As a member of the Postal Microscopical Society, I have seen too many examples of crystallisation in Numount: It is perhaps feasible that people are thinning it with the wrong solvent, and degrading it ... but I have no evidence for, or against, that hypothesis.

If you have any mature examples of Numount slides, I would be very interested to know if you find any problem.

MichaelG.

There was a time when folk were reporting developing crystals in Numount, and others said that covers easily pinged off.

These don't seem to have fared badly, and are over 35 years old in some cases.

No mountant is perfect I suspect. Also, often they are designed for particular tasks, like thin sections, and therefore don't suit thicker objects. Some have solvents that are nasty.

Whilst we know that Canada balsam has stood the test of time, by virtue of some stunning mounts still looking good, we don't know how many slides have not survived.

Interestingly, whilst Eric Marson, of NBS, introduced Numount, it wasn't always written on the slides he prepared and sold, in fact, hardly any of mine have any such information.

I would be intrigued to know if Brunel are still using the bulk stock of these chemicals they bought when Eric died in 2002, and dispensing into the 15 ml bottles. If so, the stock is quite old.

In any event, I suggest getting some mountants and trying them. Have fun making slides and learning. Does it matter if they are not perfect in 20 years time?

Mike

[mrsonchus]

If you have any mature examples of Numount slides, I would be very interested to know if you find any problem.

MichaelG.

Hi Michael, hmm interesting... I really haven't had any such problems at all - my 'oldest' mounts are about 3 years old now and still as good as the day they were made to be honest.

The combination I have always used is, FAA for fixation, Isopropanol for dehydration, Histoclear 1 for clearing, infiltration-embedding and sectioning then Histoclear for de-waxing and finally Numount mountant.
I also have but don't use very much, 'Omnimount' - which I find to be very messy as it always seeps away from the coverslip leaving a residue, unlike Numount that dries perfectly cleanly within the confines of the coverslip.
Numount also sets to a usable hardness in my dry-air dryer (at 50 deg C) after about 15 minutes - fully set after about a day I'd say...

Sounds like a problem between the de-waxing solvent and Numount. Are you using Histoclear 1 to de-wax?
This is an area that really is a source of trouble - I know from my trials of Histoclear 2 and Histoclear 3 - neither of which came anywhere close to the performance of Histoclear 1 - and incompatibility btween them and Numount, Omnimount etc is a real minefield....

Also are you using genuine Histoclear 1 (I used to buy mine from Brunel but now buy it by the US Gallon to save a little money and to keep a larger stock) rather than a 'clone'? Brunel's Histoclear is the genuine one and works perfectly.

Hope that helps a little,

John B.

[MichaelG.]

Mike and John

Many thanks for the replies

Just to clarify: I have never personally used Numount ... my experiences are exclusively as an observer of others' work.

I have a sufficient supply of Canada Balsam to keep me amused for years; but have sometimes wondered about trying Numount.

MichaelG.
.
P.S. I am, of course, an admirer of Brian Darnton's and Colin Lamb's slide-making.
.
.
Edit: I have just found this very useful paper from 1977
http://www.natsca.org/article/455

[mrsonchus]

A very handy article - thanks for the link Michael.

John B.

[MicroBob]

I don't have much experience with Canadabalsam but from what I know Euparal has the big advantage to be quite tolerant against small amounts of water in the object. So you can use alcohol as intermedium and don't have to have an additional bath in Xylol. Euparal also makes it quite easy to get a bubble free clean looking slide.

[MichaelG.]

I've been searching for evidence to support my own observations of crystallisation in Numount, and have found this compilation:

Some works by Douglas Turnbull Richardson
http://www.microscopy-uk.eu/diatomist/dtr.pdf

The two paragraphs at the end of page 17 are well worth noting [as is anything written by DTR]

MichaelG.
.
Next time I find a slide exhibiting crystallisation, I must remember to photograph the evidence.

[mrsonchus]

Great link Michael, loads to learn from it - many thanks.

John B.

[Hobbyst46]

MichaelG
Thanks for reminding of the Richardson protocols. Having looked at them once, a more thorough reading now, such pleasant comprehensive presentation of methods and observations.

[MicroBob]

@MichaelG: Thank you for reminding me of the work of Douglas Turnbull Richardson!

It really is an impressive document. In the foreword is written that Mr. Richardson asked for a computer to digitize his notes when he was 84 years old. He then started into digital photography to digitize his 35mm slides and take microphotos. This is really a remarkable way to make ones knowledge available to coming generations. It is also great that the family actually found a way to make all this information available to the public. Usually most of the gained experience is lost when an old expert dies so this is a fine example of a better solution.

On the other hand we wouldn't have much to discuss here if we alll new what the old ones have known...

Cooke/Baker/Vickers: With that high level optic development in the background it really is not wonder if the microscope objectives are good. I have a couple of them for my funny Vickers Patholette microscope.

[photomicro]

@MichaelG: Thank you for reminding me of the work of Douglas Turnbull Richardson!

It really is an impressive document. In the foreword is written that Mr. Richardson asked for a computer to digitize his notes when he was 84 years old. He then started into digital photography to digitize his 35mm slides and take microphotos. This is really a remarkable way to make ones knowledge available to coming generations. It is also great that the family actually found a way to make all this information available to the public. Usually most of the gained experience is lost when an old expert dies so this is a fine example of a better solution.

On the other hand we wouldn't have much to discuss here if we alll new what the old ones have known...

Cooke/Baker/Vickers: With that high level optic development in the background it really is not wonder if the microscope objectives are good. I have a couple of them for my funny Vickers Patholette microscope.

As the person who set up the computer for Mr Richardson, and played a part in making this publication available, it is gratifying to know that it has been worthwhile.

He really was an amazing chap, and I learnt a great deal from him. Right up until his 90s he continued to make slides, and I treasure the ones he kindly gave me.

Below is an extract from one of his slide notebooks, the sort that go out to circuit members who belong to the PMS. Typical of his meticulous level of detail that he applied to all he did.

BTW, if the originator of this topic want's to PM me, I am sure I can spare a small container of some suitable mountant, foc.

Mike

[MsLichen]

Wow, thank you for the very well thought out responses (and new rabbit holes to fall into)!

[MicroBob]

Hi Mike,
thank you for your contribution to make this wealth of information available!
There a many books on scientific matter but they tend to be very expensive. Library books are also less than ideal because you often have to give them back when you need them most, especially as a slow working part-time amateur. For this reason documents like that from Mr. Richardson a a valuable source of information.