Yesterday, to honor John on his birthday, I shared with you the key to his character: his favorite book is Shel Silverstein’s The Giving Tree. Today’s post, I hope, conveys just how much I love and admire my Valentine, and I think this picture tells more of the story.

Every two weeks, John spends a couple of hours hooked up to an apheresis machine at Virginia Blood Services. The device is a type of centrifuge which extracts the blood platelets and some of the plasma from John’s whole blood, returning the red cells and most of the plasma back to him but retaining the life-giving platelets. As I understand it, platelets are an essential part of cancer and organ transplant treatments. John has been donating either whole blood or platelets for most of his adult life; he first gave blood when he lived in Pittsburgh in the late 1980s, after learning about an area child, suffering from leukemia, who needed platelets for treatment.

I’m not afraid of needles or anything, but I’ve never given blood before. My blood pressure has always trended on the low side; I am, unfortunately, one of those people with a lower than usual supply of energy. I suppose I just assumed that giving blood would have an adverse effect on me, depleting my precious stores of vitality.

But on Sunday I accompanied John to Virginia Blood Services and, to my pleasant surprise, I passed the initial screening. I then got myself tethered to a tube and proceeded to have one pint of whole blood siphoned from myself, feeling rather like a pump at a gas station. The whole procedure took about eight minutes. And although John’s method of donating—apheresis—takes about two hours, the process is typically kinder to his system than giving whole blood, because the machine returns the vital red cells to him. Giving whole blood, in which one relinquishes red cells, platelets, plasma and all, can tend to leave a person feeling weaker than giving via apheresis. I’m glad to say, however, that after drinking a can of sugared soda at the advice of the technician (something I never do), I only felt tired, not light-headed or ill in any way.

Here are some facts, courtesy of the Virginia Blood Services website, that are worth learning if you’ve ever considered donating blood but have yet to take the plunge:

• More than 4.5 million patients need blood transfusions each year in the U.S. and Canada;
• 43,000 pints of donated blood are used each day in the U.S. and Canada;
• Someone needs blood every two seconds. Females receive 53 percent of blood transfusions; males receive 47 percent;
• In the United States, less than 10 percent of the 38 percent eligible to donate blood do so annually;
• About one in seven people entering a hospital need blood;
• One pint of blood can save up to three lives.

It’s astonishing to think that the pint of blood I donated on Sunday could save three lives. I’m ashamed that I’ve never been so selfless before this. John’s generous nature has influenced me. And that’s one of the many gifts he’s given me that money can’t buy.

Happy Valentine’s Day, everyone!