“Your blood, Cola,” Lower said to relieve my anxiety. “Tell us about your blood. What have you been up to? What experimentations are your conclusions based on? What are your conclusions, in fact?”
“I’m very much afraid I am going to disappoint you,” 1 began hesitantly when I saw they were not to be diverted. “My researches are scarcely advanced. I am mainly interested in the question of what the blood is for. We have known for thirty years that it circulates around the body; your own Harvey showed that. We know that if you drain an animal of its blood, it rapidly dies. The vital spirits in it are the means of communication between the mind and the force of mobility, permitting movement to take place…”
Here Lower wagged his finger. “Ah, you have fallen too much under the influence of Mr. Helmont, sir. There we will be in dispute.”
“You do not accept this?”
“I do not. Not that it matters, at the moment. Please continue.”
I regrouped my forces and rethought my approach. “We believe,” I started, “we believe that it moves heat from the ferment of the heart to the brain, thus providing the warmth we need to live, then vents the excess into the lungs. But is that really the case? As far as I know, no experiments have proven this. The other question is simple—Why do we breathe? We assume that it is to regulate the body heat, to draw in cool air and thus moderate the blood. Again, is that true? Although the tendency to breathe more often when we exercise indicates this, the converse is not true, for I placed a rat in a bucket of ice and stopped its nose, but it died nonetheless.”
Boyle nodded, and Lower looked as though he wanted to put some questions, but as he could see I was concentrating and trying to present my case well, he obligingly refrained from interrupting.
“The other thing that has struck me is the way in which the blood changes consistency. Have you noticed, for example, that it alters color after passing through the lungs?”
“I confess I have not,” Lower replied thoughtfully. “Although of course I am aware that it changes color in a jar. But we know why, surely? The heavier melancholic elements in the blood sink, making the top lighter and the bottom darker.”
“Not so,” I said firmly. “Cover the jar, and the color does not change. And I can find no explanation of how such a separation could occur in the lungs. But when it emerges from the lungs—at least, this is the case in cats—it is very much lighter in color than when it goes in, indicating that some darkness is withdrawn from it.”
“I must cut up a cat and see for myself. A live cat, was it?”
“It was for a while. It may well be that some other noxious elements leave the blood in the lungs, are sucked out by passage through the tissue, as through a sieve, and are then exhaled. The lighter blood is purified substance. We know, after all, that the breath often smells.”
“And did you weigh the two cups of blood to see if they had changed weight?” Boyle asked.
I flushed slightly, as the thought had never even occurred to me. “Clearly this would be a next step,” Boyle said. “It may be, of course, a waste of time, but it might be an avenue to explore. A minor detail, though. Please continue.”
Having made such an elementary omission, I felt unwilling to continue and lay out my more extreme flights of fancy. “If one concentrates on the two hypotheses,” I said, “there is the problem of testing to see which is correct—does the blood shed something in the lungs, or gain something?”
“Or both,” Lower added.
“Or both,” I agreed. “I was thinking of an experiment, but had neither the time nor the equipment in Leiden to pursue my ideas.”
“And that was… ?”
“Well,” I began, a little nervously. “If the purpose of breathing is to expel heat and the noxious byproducts of fermentation, then the air itself is unimportant. So if we placed an animal in a vacuum…”
“Oh, I see,” Boyle said, with a glance at Lower. “You would like to use my vacuum pump.”
In fact, the idea had not occurred to me before I spoke. Curiously, Boyle’s pump was of such fame I had scarcely given it a thought since I’d arrived in Oxford, as I had never dreamt of the possibility of using it myself. The machine was of such sophistication, grandeur and expense that it was known to people of curiosity throughout Europe. Now, of course, such devices are well enough known; then there were perhaps only two in the whole of Christendom, and Boyle’s was the better, so ingenious in design that no one had managed to reproduce it—or the results he attained. Naturally, its use was rationed very carefully. Few were even allowed to see it in operation, let alone employ it, and it was forward of me even to bring the subject up. The last thing I wanted was a refusal; I had set myself the task of ingratiating myself into his confidence, and a rebuff now would have been hurtful.
But, all was well. Boyle thought the matter over a while and then nodded. “And how might you proceed?”
“A mouse or a rat would do,” I said. “Even a bird. Put it in the bell and extract the air. If the purpose of respiration is to vent fumes, then a vacuum will provide more space for the exhalations, and the animal will live more easily. If respiration requires air to be sucked into the blood, then the vacuum might make the animal ill.”
Boyle thought it over and nodded. “Yes,” he said eventually. “A good idea. We can do it now, if you like. Why not, indeed? Come along. The machine is prepared, so we can start immediately.”
He led the way into the next room, in which many of his finest experiments had taken place. The pump, one of the most artistic devices I had seen, stood on the table. For those who do not know it, then I suggest they consult the fine engravings in his opera completa; here I will merely say that it was an elaborate device of brass and leather with a handle connected to a large glass bell and a set of valves through which, propelled by a pair of bellows, the air could be made to pass in one direction, but not the other. By the use of this, Boyle had already demonstrated some marvels, including the disproval of Aristotle’s dictum that nature abhors a vacuum. As he said in a rare moment of jest, nature may not like it, but if pushed will be made to put up with it. A vacuum—an area of space voided entirely of content—can indeed be created and possesses many strange qualities. As I examined the machine carefully, he told me how a ringing bell placed in a glass chamber will stop making sound as the vacuum is created around it; the more perfect the vacuum, the less the sound. He said he had .even constructed an explanation for the occurrence, but declined to inform me of it. I would see for myself with the animal, even if the rest of the experiment did not work.
The bird was a dove, a handsome bird which cooed gently as Boyle took it from its cage and placed it underneath the glass dome. When all was ready, he gave a signal, and the assistant began working the bellows with much grunting and a whooshing sound as air was propelled through the mechanism.
“How long does this take?” I enquired eagerly.
“A few minutes,” Lower replied. “I do believe its song is getting fainter, do you hear?”
I regarded the beast with interest, as it was showing signs of distress. “You are right. But surely it is because the bird itself seems unconcerned with making a noise?”
Hardly had I spoken when the dove, which a few moments ago had been hopping around the dome with curiosity, fluttering against the invisible glass walls which it could feel but was incapable of understanding, fell over, its beak gaping open, its beady eyes popping and its legs flailing around pathetically.
“Good heavens,” I said.
Lower ignored me. “Why don’t we let the air back in, and see what happens then?”
The valves were turned, and with an audible hiss, the vacuum was filled. The bird still lay there, twitching away, although it was clear that it was very much relieved. Within a few moments, it picked itself up, ruffled its feathers and resumed its attempts to fly away to freedom.