It Stained Our Fingerprints!

Today, September 27th, after our microbiology test we went into lab to do a capsule stain. To do this stain we placed a drop of nigrosin onto a slide. We then used the inoculating loop to place bacteria into the nigrosin drop. Using a clean slide we spread the nigrosin down the slide. We then let it air dry. Once the nigrosin was air dry we spread crystal violet stain over the nigrosin and waited for the stain to dry. Once the stain was dry we rinsed the excess off with water. We then blotted off the excess water and examined our new slides. Because of the capsule stain, we came to the conclusion that neither of our samples, the unknown and the dollar bill, had capsules. This is known because there was not a unstained circle around the dark bacteria.

before

during

after

As for the title, we apparently didn't clean the slide well enough and the nigrosin caught our fingerprints.