Oil immersion

[p3aul]

What's the correct procedure? I made a slide of my blood and viewed it with my 10x EP and 40X Ob All's well. That was several days ago and the slide still looks good at 400X Now i want to view it at 1000X with my 100x Oil Ob. Can I just put a drop of oil on the slide and lower my 100X into it or will that just liquify the blood an ruin everything. Is putting a coverslip down first the proper procedure or does it make a difference?
Thanks,
Paul

[rnabholz]

Hi p3aul,

Yes, you do need a cover slip over the subject before applying oil.

Center the subject using a lower power eyepiece, rotate the Oil Immersion Objective towards the observing position, but do not click into place. With the objective positioned roughly midway between the click stops, apply a small drop of oil directly onto the cover slip at the place that is illuminated by the light from the condenser. Then gently rotate the objective into the oil and secure it into the click stop.

Once you are done, be sure to blot the Oil off of the objective using a soft tissue.

Hope that helps

Rod

[lorez]

Yes, you do need a cover slip over the subject before applying oil.

I will humbly disagree here. You do not need a coverslip and will have better luck if you do not use one. The oil takes the place of the coverslip. None of the hematology labs I work in use coverslips.

When you clean your slide simply blot the oil off the slide. Wiping will also take your smear.

lorez

[rnabholz]

I defer to Lorez's experience.

I apologize for my error, I was not aware that it was common practice with blood to go without coverslips.

[p3aul]

OK thanks guys! After the blood I want to examine another slide I made of an epithelial cell also sans coverslip. Now in this case Do I put the cover slip on or no? My thinking is that without the coverslip the E. cell would just wash right off. I guess the dried blood must not be dissoluble in immersion oil. Am I wrong again? Probably!

[gekko]

OK thanks guys! After the blood I want to examine another slide I made of an epithelial cell also sans coverslip. Now in this case Do I put the cover slip on or no? My thinking is that without the coverslip the E. cell would just wash right off. I guess the dried blood must not be dissoluble in immersion oil. Am I wrong again? Probably!

This time you are absolutely right

[Charles]

There are two ways of doing this depending on if you want to keep the slide with the sample or not.

If you want to save the sample than you will need to fix the specimen...blood, cells etc to the slide (one common way to fix for blood is to pass the sample through a flame a couple of times). Then you would stain the slide (if needed) and then mount the slide in a suitable medium with cover slide and this could be saved for viewing indefinitely.

If this is just a look and you don't plan on keeping it more than a day or two, fix the sample to the slide and put the oil directly on the specimen and view to your hearts desire. It can be kept for a few days but can get contaminated after a period of time.

[p3aul]

Thanks, all of you. I appreciate the help!
Paul

[zzffnn]

What Charles said. OK to go w/o cover with oil objective (immersed in oil), but fix blood sample first in that case. Or use cover and oil with fresh (wet, not fixed) blood - you don't want cells to shift around.

Plus: for dry 40x objective, you need cover slip to get reasonable image quality. (It is not that you won't get images without cover) you will get images, just not good ones. It is up to your preference though.

[gekko]

Yes. I was replying to Paul's follow-up question regarding observing epithelial cells, and I (perhaps wrongly) assumed that he meant using the customary wet mount of the cells, in which case I think it would be necessary to use a cover glass with an oil-immersion lens (and, if good images are desired, also with high NA dry objectives, as zzffnn mentioned).

[Crater Eddie]

If you are using a hematology stain on a properly made blood smear, the stain fixes the blood cells to the slide (depending on the stain), so separate fixing is not necessary. Just be sure your smear is good and dry before staining and Bob's Your Uncle. No cover glass necessary either, just oil the objective to the slide. Store your slides in a closed container to keep dust and debris from collecting on the oil and they will be usable for a long long time.
CE

[KurtM]

"... and Bob's Your Uncle"...?

[p3aul]

Kurt, I think he's referring to the initials of a procedure but I don't know what it is.

Here is a puzzler though. I bought an old-style microscope from Edmund Scientific in the middle sixties. They referred to it as "Society Size". It had a three turret objective holder and one Ob was an oil immersion 100x It was not a toy, but a full size microscope. The stage got kinda messed up and I threw the scope away when I got my Amscope. I kept the 10x eyepiece though and last night I used it in the Amscope. It was a perfect fit, but guess what? I got a brighter image than the 10X Amsope eyepiece and the image was larger! I puzzled over that a bit and this thought came to mind. Maybe the tube length of the old microscope was different than the Amscope and this was giving greater magnification. Could that be it?

i guess I will be in the market for one of zzffnn's used Nikon EP's to check the difference!

I need some Wright's stain for the blood, I wonder what will work for the E. Cell?

[zzffnn]

Eyepiece does affect optical length and brightness/contrast. But magnification between different brands of DIN 10x eyepieces should not vary too much.

AmScope objective may need (chromatic and spherical) compensation from AmScope eyepiece, which Nikon eyepiece would NOT provide correctly (not a match). So Nikon eyepiece may not work well for you, especially in the chromatic correction aspect.

[Crater Eddie]

"Bob's Your Uncle" is Australian (I think) slang similar to "In Like Flint"... it means you are good to go.
You can get pretty good Wright's Giemsa stain from Amazon, though it's a pretty small bottle. A veterinarian supply company can get you a product called "Dip Quik", which is a very good hematology stain. I haven't tried it yet, but member Skyfog gets very good results with it.
You could even try that on the epithelial cells, or get some methylene blue.
CE

[p3aul]

Thanks for the suggestion Eddie! I have a friend who's a Vet and I bet he would give me some wright's stain and some immersion oil for that matter. In the 60's when I had the first Scope I bought some Wright's Stain from a Medical supply place. They probably have all kinds of laws in place now, so the wouldn't sell to a hobbiest.

Well phooiee about the Nikon EP's zzffnn! I'm sure they are probably 30mm or larger and wouldn't fit anyway. It could be that the old eyepiece was just better quality anyway, but I DO know there was an increase in Mag.

[zzffnn]

My Nikon CFW10 eyepieces are actually old standard 23mm and will fit all tubes of that size. It is just that AmScope's original EPs theoretically may be the best optical fit for AmScope objectives. YMMV though.

30 mm compound EPs are common for modern infinity scopes and some old Leitz use that size too. But they go with specific objectives designed to project that wider view.

[charlie]

"... and Bob's Your Uncle"...?

Bob's your uncle
It's a catch phrase dating back to 1887, when, in a blatant case of favoritism, British Prime Minister Robert Cecil (a.k.a. Lord Salisbury) decided to appoint his nephew Arthur Balfour to the prestigious and sensitive post of Chief Secretary for Ireland.

So "Bob's your uncle" is another way of saying "your success is guaranteed."

http://www.urbandictionary.com/define.p ... your+uncle