buyer beware!

Here you can discuss sample and specimen preparation issues.
Post Reply
Message
Author
neal Shields
Posts: 58
Joined: Sat Jun 04, 2022 8:02 pm

buyer beware!

#1 Post by neal Shields » Sat Feb 25, 2023 4:04 pm

Sometimes you get the bear and sometimes the bear gets you.

I am a BIG fan of old slides.

Recently I saw an eBay listing for slides from a marine biologist's estate sale.

(Note: I have NO quarrel with the seller, she/he listed exactly what she had and was clear she/he hadn't looked at them under a microscope.)

"Pigs get fat and hogs get slaughtered". They were cheap! About 50 cents each and a nice box.

https://www.flickr.com/photos/196001110 ... ed-public/

The blue dots are where the maker marked the sample so it would be easy to find.

I have always wondered why you can't just take an insect, bug, tardigrade... and entomb them in mounting media without first drying them out and preserving them.

Now I know.

Each slide had 3 or 4 samples per slide and there were about 60 slides. (I have never seen cover glasses that small)

As near as I can tell, NONE of the specimens (all carefully labeled by species and genre) survived.

Someone put in hundreds of hours of collecting, documenting, mounting and research, to make these slides and all that work is, "gone with the wind".

In very few cases a carapace has survived and on one slide there is a perfect impression of a copepod in the medium but the actual animal has long since evaporated.

The slides are about 50 years old.

ldflan
Posts: 134
Joined: Wed May 22, 2019 11:36 pm
Location: Morna Moruna

Re: buyer beware!

#2 Post by ldflan » Sat Feb 25, 2023 5:39 pm

Small insects will clear to complete transparency - completely invisible- in Berlese's medium, for example. Try checking with DIC.

neal Shields
Posts: 58
Joined: Sat Jun 04, 2022 8:02 pm

Re: buyer beware!

#3 Post by neal Shields » Sun Feb 26, 2023 3:40 pm

This is as good as it gets under DIC.

This may be as good as it ever was but it isn't what a modern insect whole mount looks like.

I took this to be the hole in the mounting medium where the specimen was.


https://www.flickr.com/photos/196001110 ... ed-public/

ldflan
Posts: 134
Joined: Wed May 22, 2019 11:36 pm
Location: Morna Moruna

Re: buyer beware!

#4 Post by ldflan » Sun Feb 26, 2023 3:58 pm

Perhaps the insects were cleared in KOH before mounting in Berlese's, but insufficiently washed? Too bad...

AntoniScott
Posts: 108
Joined: Tue Dec 24, 2019 3:54 pm

Re: buyer beware!

#5 Post by AntoniScott » Tue Apr 11, 2023 11:43 am

Buying old or vintage slides is a "hit" or "miss" endeavour. I have very few vintage slides because of the poor quailty of the remaining specimin.

Some slides will last a hundred years depending on the quality of the original preparation. Back in the old days of the early 1900's up until the late 1900's, the mounting medium of choice was Canada Balsam, but in most cases over time it would yellow and crack from drying. The older slides with the black ring around the coverslip did a good job of preventing the cracking from drying.
Today we have a mounting medium, like Fisher Permount, that is said to be resistant to yellowing and cracking, but only time will tell.
My collection of vintage slides is for historical purposes only, not for critical viewing of structures. I do have some old diatom slides that have survived the ravages of time.
Antoni

Post Reply