The Fiery Cross - Diana Gabaldon [594]
I hadn’t any crystal violet or carbofuchsin, but I had been able to produce a reddish stain that made epithelial cells highly visible, if only temporarily. It remained to be seen whether the same stain would work on red blood cells and their inclusions, or whether I should need to try differential staining.
“What is in them?” Roger turned to look at me, interested.
“Plasmodium vivax,” I said. “The protozoan that causes malaria.”
“You can see it? I thought germs were much too small to see, even under a microscope!”
“You’re as bad as Jamie,” I said tolerantly. “Though I do love to hear a Scotsman say ‘gerrrms.’ Such a sinister word, spoken in a deep voice with that rolling ‘r,’ you know.”
Roger laughed. The hanging had destroyed much of the power of his voice, but the lower, harsher registers remained.
“Nearly as good as murrrrderr,” he said, rumbling like a cement mixer.
“Oh, nothing’s as good as ‘murrrderr’ to a Scot,” I assured him. “Bloody-minded blokes that you all are.”
“What, all of us?” He grinned, plainly not minding this gross generalization in the least.
“To a man,” I assured him. “Mild enough to look at, but insult a Scot or trouble his family, and it’s up wi’ the bonnets of bonnie Dundee. All the blue bonnets are over the border, and next thing you know, it’s lances and swords all over the Haughs of Cromdale.”
“Remarkable,” he murmured, eyeing me. “And you’ve been married to one for . . .”
“Quite long enough.” I finished my sponging and rinsing and blotted the back of his hand, small red patches soaking into the fresh gauze. “Speaking of bloody men,” I added casually, “do you happen to know your own blood type?”
One dark brow went up at that. Well, I didn’t mean to slip it by him, after all; I’d only wanted a way to broach the question.
“Yes,” he said slowly, “I do. It’s O-positive.”
The dark green eyes were fixed on mine, steady with interest.
“Very interesting,” I said. I replaced the gauze square with a fresh one, and started winding a bandage around it.
“Just how interesting is it?” he asked. I glanced at him, and met his eyes.
“Moderately.” I drew out the slides, dripping pink and blue dyes. One slide I propped against the milk jug to dry, the other two I exchanged, putting the pink slide into the blue stain, and vice-versa.
“There are three main blood groups,” I said, blowing gently on the propped-up slide. “More really, but those three are the ones everyone knows about. It’s called the ABO grouping, and everyone is said to have type A, type B, or type O blood. The thing is, like all your other traits, it’s determined genetically, and—human beings being heterosexual, generally speaking—you have one half your genes for any trait from one parent, the other half from the other.”
“I dimly recall that bit from school,” Roger said dryly. “All those bloody charts—excuse me—about hemophilia in the Royal Family, and the like. I assume it has a certain amount of personal significance now, though?”
“I don’t know,” I said. “It might have.” The pink slide looked dry; I laid it gently on the stage of the microscope and bent to adjust the mirror.
“The thing is,” I said, squinting through the eyepiece as I twiddled the focusing knob, “those blood groups are to do with antibodies—little odd-shaped things on the surfaces of blood cells. That is, people who are type A have one sort of antibody on their cells, people with type B have a different sort, and people with type O don’t have any at all.”
The red blood cells showed up suddenly, faintly stained, like round pink ghosts. Here and there a blotch of darker pink indicated what might be a bit of cellular debris, or perhaps one of the larger white blood cells. Not much else, though.
“So,” I went on, lifting the other two slides from their baths, “if one of his parents gave a child the gene for type O blood, and the other gave him one for type A, the child’s blood will show up as type