Chapter 51

"So, how would you tell what blood group this is?" Travis asked, looking at what I was doing intently.

Travis had told me that he hasn't reached this far at his previous college and he wasn't here as yet when Mrs. Harriot had done it with us. So, he had asked me to explain it to him.

I indicated the three test tubes that were placed on the table as I spoke. "In this test tube, there is an anti-A antibody, in this one, anti-B and the other is a control solution. I'm going to add the blood to each." I then tip a drop of the blood into the three test tubes.

We observe each test tubes to see whether the red blood cells have agglutinated or simply settled to the bottom. Soon, we noticed that in the test tube containing the anti-A antibody, the blood has settled to the bottom. There was no reaction in the other two test tubes.

I turn to Travis with a look of satisfaction. "This means that this blood type is A."

"How so?" He asked.

"Because the red blood cells match with the A antigens." I p