Histology (Part 1): Cutting, embedding, and staining dead @%$# since 1771

Hello, people, it's the post you've been waiting for...finding out WTF I do in lab besides dig around in a large dirt container full of live fish bait. Well, now that you know about muscles and hydrostatic skeletons (remember, the fluid filled structure surrounded by flesh and muscle, kind of like a pipe or an erect penis? I knew if I said penis it would come back to you!) I can tell you!

Worms, a living pipe

I am basically cutting up worms to look at worm's muscle and fluid filled skeleton to see how different variables affect these dimensions. As you may remember, the cross sectional area of muscle is proportional to force production, so if I know how big worm's muscles are I can predict how much force that worm can produce. If I know how large the fluid filled skeleton is, I can guess how much stress the skeletal fluid is putting on the muscles and body wall that surround it, kind of like how much stress pipe walls have when they are filled with water. You can imagine if the muscles are under a lot of stress, the worm may not want to contractthem too hard or else the pressure in the fluid cavity will increase, increasing the stress on the muscles, potentially making the worm burst! I accidentally did this once... I normally use a 10% ethanol, 90% water solution to drug my worms before I cut them and one time I forgot to add the water and put the worm in a 100% ethanol solution and it seized up all of its muscles and blood started spurting out because the worm's body wall was under so much pressure it burst...kind of like a pipe wall under too much water pressure. Or kind of like an aneurysm in your blood vessels, which I nearly had when I realized what I did. Oops!

So, how do I look at these dimensions? I use what is called histology. You know when you were in high school and looked at stained microscope slides of skin cells or protists or whatever? That is the end product of histology. All you really do is kill the thing you want (don't cry for my worms, they have got to a better place where they can have all the moist dirt they'd ever need), cut up the part you want to look at, embed it in something hard to make cutting it easier, slice it up, put your slices on a slide, and stain them. The end product is something much more colorful and aesthetically pleasing than the live critter you were looking at, and it makes it easy to tell different tissue types apart, like muscle in my case.

So here is the first part on how I kill and slice earthworms. I'll show you the rest next time!

Here is a pic of a drugged earthworm in 10% ethanol. Sorry, I did not take a pic of the exploding worm, I was too busy freaking out.

He/she is so wasted right now.

Here is a pic of my mad scientist worm cutting station. Basically what I do is cut the worm into pieces, then I will cut the pieces further to get specific segments, and I will measure and compare these segments to other earthworms. I have been looking at segments 10, 20, and 30 (starting at the head) in worms because these segments can be different from each other down the length of the worm and segments in the first half of the worm are the most important for movement and burrowing. The tail of the worm is basically dragged along when the worm moves, so I focus on the front half of the worm.


See the jars? That is where the worm parts go, yum!



I then weigh and measure the worm and plop him on the 'surgery table'. You can see the worm is limp and motionless from being drugged and I promise he/she didn't suffer (at least not nearly as much as a worm on a hook!).




RIP: Wormy. 

 The last step is to cut the worm into pieces and out the pieces in jars. I actually go back the next day and slice the pieces into the specific segments I want. Now I have the worm pieces I need to embed the worms in plastic!

Worm heads in jars, the next must have for the fall season.

You can see I cut the head even more so now I just have the segment I want.

Hope you enjoyed my worm murdering, stay tuned for embedding, cutting, and dying worm parts! I know you can't wait!

Your favorite mad scientist,

The 'Dirty' Scientist.