In Demo Veritas

Exploding mouse red blood cells

I suppose I’m taking a chance, what with the law about visualizations of animal cruelty still under consideration by the Supremes.   I feel a little cruel making my dog sit and wait (and drool) for her dinner, so I’m not being flip about this.

I brought our crufty video enabled microscope over to Pfizer lecture hall over in the Mallinckrodt building.  (Who pays for these place names?  Oh, yeah.)  A video projector was set up on the side screen, with the main, center screen for the professor’s powerpoint.  I prepared a microscope slide as follows in the scanned notebook page:

The procedure for mouse blood is the same as for cheese, except substitute mouse blood for milk, and hypertonic salt solution and distilled water for the acetic acid.  With a pipette, a very small drop of mouse blood  is placed on the slide, and the cover glass put in place.  First with the 10x objective, and then with the 40x I focused on the blood.

In fact it is really hard to see individual red blood cells in a thick sample of blood.  The parafilm is thick, makes a deep well.  Putting the cover slip down on the drop of blood, which smooshes the drop flat, makes the individual red blood cells easier to see.  Next time I think a sample of blood diluted in normal saline would be better, and would allow us to see the normal red blood cells more clearly before shrinking them in concentrated salt solution, or inflating them in distilled water.

Flood the sample with distilled water and watch the red blood cells swell up into little balls.  Using a straight razor blade, cut a channel from the side to the well.  The cover slip is over the well and half of the channel.  A drop of water placed on the channel wicks into the well.  Everything microscopic zooms around for a second, then stop.  The osmotic action is pretty fast at this scale.

With milk and acetic acid, the action is a little slower, as the protein forms filaments that lock the fat globules in place.  The fat still jiggles, but the globules don’t move around anymore, after about a minute.   Microscopic cheese!