Sugden stuck his white thatch in the door. "May we come in?" He introduced a man as Dr. Dumville of the Cornell Medical Center. Brock knew the physiologist by reputation and was only too glad to explain his work.
"You're of course familiar, Doctor," he said, "with the difference between lung tissue and gill tissue. For one thing, gill tissue has no mucus-secreting cells to keep the surfaces moist out of water. Hence the gills dry and harden, and no longer pass oxygen one way and carbon dioxide the other as they should. But the gills of many aquatic organisms can be made to function out of water by keeping them moist artificially. Some of these forms regularly come out of water for considerable periods, like the fiddler crab and the mud skipper, for instance. They're all right as long as they can go back and moisten their gills occasionally.
"But in no case can a lung be used as a gill, to extract oxygen dissolved in water, instead of absorbing it from the air. I've been studying the reasons for this for some years; they're partly mechanical--the difficulty of getting anything as dense as water in and out of the spongy lung structure fast enough--and partly a matter of the different osmotic properties of the breather cells which are each adapted to operate on oxygen of a given concentration dispersed in a medium of given density.
"I've found, however, that the breather cells of lung tissue can be made to react to certain stimuli so as to assume the osmotic properties of gill tissue. It consists mainly of a mixture of halogen-bearing organic compounds. A good dose of the vapor of that stuff in the lungs of one of the young alligators in this tank should enable him to breathe under water, if my theory is correct."
"I'd suggest one thing," said Dumville, who had been giving polite but interested "uh-huh's," "which is that when you hold your alligator under water, his glottal muscles will automatically contract, sealing off his lungs to keep out the water, and he'll suffocate."
"I've thought of that, and I'll paralyze the nerves controlling those muscles first, so he'll have to breathe water whether he wants to or not."
"That's the idea. Say, I want to be in on this. When are you going to try out your first alligator?"
They talked until Sugden began clearing his throat meaningfully. He said, "There's a lot more to see, Dr. Dumville. You've got to take a look at our new extension. We certainly sweat blood getting the city to put up the money for it." He got Dumville out, and Brock could hear his voice dying away: "...it'll be mostly for new pumping and filtering machinery; we haven't half the space we need now. There'll be two tanks big enough for the smaller cetaeca, and we'll finally have some direct sunlight. You can't keep most of the amphibia without it. We had to take half the damned old building apart to do it..." Brock smiled. The extension was Sugden's monument, and the old boy would never retire until it was officially opened.
Brock turned back to his apparatus. He had just begun to concentrate on it when Sam Baritz stuck his gargoyle's face in. "Say, Vuinon, where ya gonna put the bichir? It gets in tomorrow."
"Mmm--clear the filefish out of 43, and we'll make up a batch of Nile water this afternoon for it. It's too valuable to risk with other species until we know more about it. And--oh, hell, put the filefish in a reserve tank for the present."
That means another new label, he thought as he turned back to his chemicals. What would be a good wording? "Esteemed as food..." Yes. "Closely related to fossil forms"? Too indefinite. "Related to fossil forms from which most modern fish and all the higher vertebrates are descended." More like it. Maybe he could work in the words "living fossil" somehow...
In his abstraction he hadn't noticed that the flask into which the oily liquid was dripping had been nudged too close to the edge of the table. The slam of a dropped plank from the extension where construction was still going on made him start nervously, and the flask came loose and smashed on the floor. Brock yelped with dismay and anger. Three weeks' work was spread over the floor. He took his morning paper apart and swept up glass and solution. As he knelt over the wreckage, the fumes made his eyes water. In his annoyance it never occurred to him that a man's lungs aren't so different from an alligator's.
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