Although Cousteau, Link and the others deserve more attention than they now get, there has been some criticism of their operations. The prolonged dive planned by Link, Stenuit and Lindbergh is unprecedented. No diver has ever been exposed to similar conditions for more than 24 hours, even in the simulated environment of a compression chamber on land. The critics ask: Why not study the effects on the human system in a compression chamber before venturing into the uncontrollable sea? The answer perhaps lies in the zeal of the three men. They were eager to find out; they were too restless to wait.
As for Cousteau, some divers feel he is not passing on as much knowledge as he could to others who are working to live underwater. In his account of life under the Red Sea last summer, Cousteau dotes on the beauty seen through the window of an underwater house and tells how he enjoyed a reeking Tuscan cigar after dining 36 feet below with five members of his team who lived there for a month. He reports that the champagne was flat because of the increased pressure, and he discourses on the odd behavior of wild and half-tame fish. Such an account popularizes undersea living but does not do much to advance it. It has been a year now, for example, since Cousteau's men, Kientzy and Portelatine, exposed themselves to a rather exact set of conditions that no man had tried before, even in a laboratory. Yet there has never been a physiological report on either of the men. This much is known: they are alive, sleeping and eating well and enjoying good wine. But there are physiologists in both hemispheres who would like to know much more about Kientzy and Portelatine—about their hearts, their lungs, their circulatory systems, their blood chemistries and their urine.
The gravest problems of undersea living lie within man. The human body is remarkably well designed to stand the direct effect of pressure underwater. But the indirect effects of pressure are something else again. The tissues of the body use only one gas, oxygen, but, in a curious way, the inert nitrogen that is inhaled and the toxic waste gas, carbon dioxide, that is exhaled are also important. The overburden of carbon dioxide in the system is the principal stimulus to breathing. The 78% nitrogen in our air serves as a diluent, cutting the oxygen down to a level that humans can live with. High concentrations of oxygen, if breathed too long, are toxic, a 55% concentration being about the tolerable limit for long periods at sea level.
Safe breathing mixtures are fairly easy to maintain. The only trouble is that a mixture that is safe at sea level can be dangerous and deadly in the increasing pressure below. The 21% oxygen in natural air is safe at very shallow depths, but at 66 feet it is more than a man can tolerate for long, and at 300 feet it is highly toxic. Similarly, the carbon dioxide concentration that a man must often tolerate in a fetid, car-choked city is more than he can stand at considerable depth. And, as even novices know, the inert gas, nitrogen, becomes increasingly narcotic as a diver descends. To make things worse, there are synergistic effects—evil collusion of the gases, you might say—that aggravate the dangers man faces below. The retention of too much carbon dioxide tends to increase the narcotic effect of nitrogen, and physiologists suspect that it also contributes to the toxic effect of oxygen. Nitrogen dulls the respiratory center of the brain, increasing the chance of anoxia or excessive buildup of carbon dioxide.
Some problems—notably narcosis and the gross density of the breathing mixture—are obviated by substituting a lighter inert gas, helium, for nitrogen. Oxygen toxicity can be prevented by lowering the oxygen percentage proportionately as the pressure increases below. To complicate matters further, men were not created equal for the sea. Some men tolerate the effects of pressure far better than others, for reasons not wholly understood.
In the past 60 years there has been much study of these problems, but virtually all of it was aimed at getting man down for short visits. Not until six years ago did anyone venture very far along the trail of research that will lead to permanent settlement of the sea. If Cousteau and the others deserve a plaque in the town hall of the first underwater community, a statue of that first pathfinder should be erected in the center of the town square. The name: Captain George F. Bond.
Bond, a 49-year-old Navy doctor, first publicly suggested living in the sea in 1957, but he takes no credit for it—he came across the idea while reading the writings of a 15th century English bishop. Then, in October 1958, without any breathing apparatus, Bond and Navy Chief Cyril Tuckfield left the escape hatch of the submarine U.S.S. Archer-fish at a depth of 302 feet. Carefully breathing out the single massive breath of air they had packed into their lungs in the hatch, they made the surface in 53 seconds and proved that the hitherto accepted submarine escape depth of 100 feet was far short of the potential limit. Sport divers who might be tempted to try the same thing with their brand-new scuba rigs should note that there are half a dozen different ways of dying en route up. Bond's dramatic ascent was preceded by much thinking and calculating and by practice at lesser depths.
Although he is a man of imagination, Captain Bond examines all new ideas, including his own, with the skepticism of a pawnbroker. About seven years ago he and his colleagues began a series of tests that exposed a variety of animals for prolonged periods to various breathing mixtures at pressure equal to 200 feet. In these tests Bond tried natural air (lethal), pure oxygen (lethal), a mixture of 97% nitrogen and 3% oxygen (definitely harmful), and a mixture of 97% helium and 3% oxygen (successful).
These tests, along with others, served as the departure point for the undersea experiments by Cousteau and Link. The fact that animals survived in helium-oxygen for 12 days indicates that man probably could, too—and Cousteau and Link acted on that conclusion—but the evidence was not compelling enough for Bond. He does not believe in guessing when knowing is possible. He frequently says, "It makes no sense to go underwater or anywhere else unless you know how you got there."
He began a series of simulated undersea tests on men, exposing them for prolonged periods to helium-oxygen mixtures at sea level and then at pressures equivalent to those at depths of 100 and 200 feet. Early in July, as a result of these tests, Bond will direct an operation in which four Navy men will try living for three weeks 192 feet down on an Atlantic rise 26 miles off Bermuda. Their 40-foot cylindrical house has all the homey charm of a Civil War submarine. It is in fact a scrap job, made of the fore and aft sections of experimental minesweeping floats. But it is safe, and if the sea can only keep its temper the test should be a success. The hearts and temperatures and pulmonary functions of the men will be checked daily. Blood and urine samples will be brought to the surface and analyzed. If Bond's undersea men should contract some new kind of undersea measles, it will be the best-documented measles epidemic in history, and in any case the cause of undersea development will have achieved a tremendous step forward.