MicrobeHunter.com Microscopy Forum

Hello,
I got a new specimen cabinet and while organizing my collection I found this odd slide. Is this just a manufacturing error or is there some purpose to mounting a specimen on a tapered slide?
Thanks,
Kirby

That is unusual. I've never seen a slide like that. I don't see how the taper would help with view that specimen. It would make it more difficult to view because you would be constantly trying to get it in focus. Probably just a defect in that slide.

Hi Charles,

Thanks for commenting.

I kind of wondered if it was created as a test of some sort but I have no idea what that could be. Otherwise I see no obvious explanation other than a mistake. Seems strange that someone would miss that during mounting but I'm certainly not exempt from such foul up!

Kirby

For me this is an interesting problem from the manucafturing side: How was this glass made? With todays float glass it is probably difficult to get such a taper. Our house is 75 years old (material perhaps a lot older) and some of the old window panes showed some interesting irregularities that are not found on today's glass.

Do you have the means to test the two surfaces for evenness?

Element 56 wrote: ↑

Mon Jun 22, 2020 3:12 pm

Seems strange that someone would miss that during mounting ...

Seems like it could be intentional, not for any optical reason, but to save money. Maybe someone bought some defective/rejected slides at a discount? Or the manufacturer donated them to the university for students to practice on?

Hi Bob!

MicroBob wrote: ↑

Mon Jun 22, 2020 3:22 pm

For me this is an interesting problem from the manucafturing side: How was this glass made? With todays float glass it is probably difficult to get such a taper. Our house is 75 years old (material perhaps a lot older) and some of the old window panes showed some interesting irregularities that are not found on today's glass.

I have replaced some windows in old farm houses with that not so clear glass. Some of it is pretty bad! I wonder if they used the Fourcault process to make microscope slides

MicroBob wrote: ↑

Mon Jun 22, 2020 3:22 pm

Do you have the means to test the two surfaces for evenness?

Yes, I can check it with my surface gauge! Now I just need to remember which drawer I put the slide in!

Kirby

I don’t pretend to have any idea why it was made that way, but I can’t imagine that is was accidental. The taper is too pronounced to be overlooked.

Element 56 wrote: ↑

Thu Jun 18, 2020 8:10 pm

Hello,
I got a new specimen cabinet and while organizing my collection I found this odd slide. Is this just a manufacturing error or is there some purpose to mounting a specimen on a tapered slide?

.

I have an idea, Kirby [but no substantiating evidence]
... I am no histologist, so this might be nonsense; but here goes:

The specimen is one in which surface details are significant, and would be best viewed ‘without coverslip’ ... but is here presented as a mounted slide [perhaps as a reference sample].

acute nephritis, kidney, exudative type

Axial incident lighting would be reflected from the coverslip, causing flare.
... This can be mitigated by tilting the slide, to divert the reflection.

So: make the slide wedge shaped, to achieve the same effect with the slide correctly located on the stage.

MichaelG.

Depending on the process there might have been a small percentage of really good slides and a lot of ones of barely usable quality. For economic reasons they may have been used it at all possible. I think I read that old slides also varied in thickness a lot, which would be a problem for high power dark field use.

Some interesting thoughts! Thank you all for commenting.

I did check it with my surface gauge and it is uneven. The tapper is about .040" across the length which is pretty extreme. There is about a .005" deviation across the width on both ends and the slide does not lay flat against the surface plate. It kind of rocks side to side which makes me thing it was just a dud!

I should, just for fun, check some of the other slides from that lot to see what there tolerances are. As someone mentioned I find the thicknesses vary with my older slides. I have some that don't fit between the slots on modern slide boxes. A good reason to keep those old wood ones around!

Kirby

That it doesn't even lay flat is what stands out most to me, talk about bad quality control.

I think it is very unlikely that a production process delivers perfect flat 1mm slides all day and then this one. So it is probably the result of a much more limited production process, probably hand made from a blown ball of glass, flattened, stetched out, cut to pieces. It probably is really old, 150 years or so, and a nice collectible and discussion topic.

Bob, I think you're on to something - the Columbia College of Physicians and Surgeons was founded in 1767. Can't tell from the photo, Kirby, is there a date on the slide as well as the college name?

https://www.ps.columbia.edu/about-us/hi ... d-surgeons

Can't tell from the photo, Kirby, is there a date on the slide as well as the college name?

Looks like 19th of March 1911 ... I don't suppose it could be 19th of March 1811?

The owner of this site : http://www.victorianmicroscopeslides.com/slide1840.htm
would probably be interested, and may be able to advise.

MichaelG.

.

P.S. ___ this annotation to a rather effective image may give some credence to my earlier suggestion:

Injected and corroded kidney section showing structures (combination transmitted and reflected lighting).

.
Ref. http://www.victorianmicroscopeslides.com/slidehis.htm

Hi,

I'm no expert on antique slides but I'm pretty sure slide is from 1911 for two reasons. First in my experience the label is indicative of the 1890's to maybe the late 1920's. Second is the size of the slide. This is not definitive by any means but if my memory serves me around 1835 is when this size started showing up. Please don't take any of that as historically accurate. It is just my observations from my collection and going from my memory, information I may have read somewhere. I will add that after collecting slides for a while one starts to get a "feel" for the time frame they were made and this one feels 1900's to me!

MichaelG. wrote: ↑

Wed Jun 24, 2020 8:36 am

The owner of this site : http://www.victorianmicroscopeslides.com/slide1840.htm
would probably be interested, and may be able to advise.

MichaelG.

Michael,

That's a great idea! I will do that and report back.

dtsh wrote: ↑

Wed Jun 24, 2020 3:51 am

That it doesn't even lay flat is what stands out most to me, talk about bad quality control.

Some of the other slides in the collection do exhibit some unevenness.

PeteM wrote: ↑

Wed Jun 24, 2020 6:53 am

Bob, I think you're on to something - the Columbia College of Physicians and Surgeons was founded in 1767. Can't tell from the photo, Kirby, is there a date on the slide as well as the college name?

This as well as others in the collection are marked Coll. Phys. & Surg. Columbia Univ. NY. Most are mounter marked "MH" and some also say H+P.A.F. I have to dig thought them again but I think one even had a patient's full name on it!

Thank you all for your thoughts on this and by all means please continue to share. I really appreciate it!

Kirby

As suggested I asked the owner of the Victorian microscope slide site, http://www.victorianmicroscopeslides.com/history.htm and he very kindly replied with his thoughts. He felt that the slide was just a defect. Since it was made by medical students it suited it's purpose and ultimately would not have had any negative effect when viewing. He added that the standard non-plan objectives of the period regularly required refocusing so one may not even noticed the tapper. Regarding the date he agreed it's definitely from 1911. He added, "Another obvious reason is the thin sectioning and staining used, which looks to be haematoxylin and eosin (H&E), as this protocol was only first introduced in 1876." I thought that last part was very interesting and valuable information for dating similar slides.

Thanks to all who shared thoughts on this!

Best Regards,
Kirby

Element56,
Found the discussion quite interesting.
Have you tried putting the slide between two polarizers to see if it is a wave/retarder plate?
Back in the late 1800's Jacques Babinet was already using compensators.
Here is Wikipedia's entry, paragraph 3 discusses his wedges of quartz.
Just wondering if a student might have mounted the specimen on a wedge????
Would be interested if you notice any birefringence or phase shifting.

https://en.wikipedia.org/wiki/Jacques_Babinet

One way or another let us know what you see!

V

Voyager-1 wrote: ↑

Tue May 04, 2021 11:47 pm

Element56,
Found the discussion quite interesting.
Have you tried putting the slide between two polarizers to see if it is a wave/retarder plate?
Back in the late 1800's Jacques Babinet was already using compensators.
Here is Wikipedia's entry, paragraph 3 discusses his wedges of quartz.
Just wondering if a student might have mounted the specimen on a wedge????
Would be interested if you notice any birefringence or phase shifting.

https://en.wikipedia.org/wiki/Jacques_Babinet

One way or another let us know what you see!

V

Hi V,
that's a really good point! May be some early two-dimensional birefringence mapping going on with this specimen (whatever that means!)
I will take a look with my petrographic and report back!
Thanks,
Kirby

I think the taper of the slide is entirely intentional. The kidney specimen is infected with lupus. How much did they know about lupus in 1922? Might the taper have been there to track to flow of liquid through the specimen as they struggled to better understand the affects of disease regarding organ function before making the slide permanent? Science has indeed come a very great distance sing 1911.
Greg

Greg Howald wrote: ↑

Wed May 12, 2021 12:05 pm

I think the taper of the slide is entirely intentional. The kidney specimen is infected with lupus. How much did they know about lupus in 1922? Might the taper have been there to track to flow of liquid through the specimen as they struggled to better understand the affects of disease regarding organ function before making the slide permanent? Science has indeed come a very great distance sing 1911.
Greg

Hi Greg,
That's an interesting observation, and quite possible.
Thank You,
Kirby

HEY YOU TRY MAKING SOMETHING LEVEL ON A SHIP.. ;-P

EYE C U wrote: ↑

Wed May 12, 2021 2:05 pm

HEY YOU TRY MAKING SOMETHING LEVEL ON A SHIP.. ;-P

Maybe the stage was a bit off kilter!

Hi Kirby, hi all. In my astronmy hobby I have a 'lucite'...some sort of plastic clip-board. With a tiny LED light bar on it's top...outdoors in the dark, this board due internal reflections of the red illumination , this entire board gently glows due the light-guided through it..and due internal reflections of that illumination. Star charts, sketch paper picks up enough of that soft red glow to be read, or sketched on in total darkness. Night-vision is not impacted by use of this clipboard while observing with your telescope.

Please light up a LED tiny torch and see how this prepared slide internally reflects the illumination, see if like a boat-deck light guide, or like my outdoor clip board, see if the specimen offers enhanced contrast due the glow of this wedge-slide.

That is a thick swath of tissue...naked eye I can sense the infiltrate of WBC's...the wedge-slide might permit a better appreciation of the altered tissue structures...just my quess mind you.

I squeemishly post into this thread late, my schedule is terrible these days..happy spring time all. charlie guevara, finger lakes/US

Voyager-1 wrote: ↑

Tue May 04, 2021 11:47 pm

One way or another let us know what you see!

V

charlie g wrote: ↑

Sun May 16, 2021 2:41 pm

Please light up a LED tiny torch and see how this prepared slide internally reflects the illumination, see if like a boat-deck light guide, or like my outdoor clip board, see if the specimen offers enhanced contrast due the glow of this wedge-slide.

Charlie & Voyager,

I tried both of your ideas and did not see anything remarkable to suggest this is intentional. Maybe there's a reason that is out of my capability of understanding but for all intense and purpose that I'm aware of this is a usable sample even with the taper. I think it's probably a manufacturing anomaly or may be this was even a common occurrence back then. Today we find something like this and thinking nothing of it we throw it in the trash. Back then they probably appreciated things a little more and used everything they could. I have similar specimens that are mounted with broken cover glass (you can tell it didn't break post mount) and if you read books from the late 1800's and early 1900's they always talk about washing and reusing slides and coverglass. They were frugal and probably especially so in an educational setting.

Thanks for the ideas!

Kirby

If you had 2 of these beveled slides you could stack them like opposing shims. The top and bottom of the stack would be parallel. The thickness of the stack could be easily adjusted by sliding the top slide back & forth. That could be a crude focus technique for ancient scopes. I would look for a second beveled slide, probably unlabeled that could be used under the labeled one.

Hi again,' element 56'...Slides are produced by totally different manufacturers from end-user histologists, pathologists, microscopists, and hobby-microscopists.


The dedicated treatment of this tissue slide you kindly share with our forum ( tissue processed, tissue sectioned, tissue stained to a particular stain -series selection, tissue mounted, slide labelled, etc. .)...all this precise protocol suggests no way would a defective microscope slide be used for the important marvel of a prepared tissue slide ( I think you said human tissue?).

Complex architecture of so many organs, and even of tissues often suggest 'sweet spots' of tissue section thickness for proper diagnosis, for gross/macro/ micro / understanding of a disease process.

I again suggest you employ oblique illumination(by LED torch to the 'thick side' of this slide-prep), lower magnification scans of slides likes your current slide , may well offer a '3 D effect' useful to clinicians.

This microscopy superceded by current technologies...but I offer a related instance where thick tissue sections observed with oblique illumination may well be documented and archived for medico-legal records...a person recovered from a lake, or marine waters...thick sections of the kidney tissues may harbor and depict diatom frustules in the glomerulie complexes ( the person was alive when they entered the waters, observed diatoms indicate body of water they entered while living)...a thick section...not too thick...not too thin..most efficient to encounter diatoms in kidney tissues..scan with oblique illumination better than simple dark field illumination with certain thickness of tissue sections.

Try and date this curious wedge slide, try and see if it is from a teaching institution...and thanks for your kind microscopy sharing. charlie g
















































































































d

jwellsy wrote: ↑

Sun Nov 20, 2022 11:54 pm

If you had 2 of these beveled slides you could stack them like opposing shims. The top and bottom of the stack would be parallel. The thickness of the stack could be easily adjusted by sliding the top slide back & forth. That could be a crude focus technique for ancient scopes. I would look for a second beveled slide, probably unlabeled that could be used under the labeled one.

.

That makes a lot of sense

Although I don’t recall ever seeing such a thing … it would be a very simple bit of engineering to make a supplementary stage which did this.

MichaelG.