My eyes were open. I was standing beside Nona and she was looking up at me. Through the half-light of the water I could see her almost as plainly as through air. She smiled encouragingly at me, and I tried to smile back. I was drawing the water in and out swiftly now, with my mouth held extended like an expiring fish. It was a tremendous effort, this respiration. The muscles of my chest and diaphragm were tired in a moment. A weight in my chest seemed smothering my heart; I seemed on fire inside—a million inflamed little lung passages rebelling at this unaccustomed medium. Spots were dancing before my eyes. I was losing consciousness through lack of oxygen. The poisoned venous blood was dulling my brain. Then I began to feel better. I was respiring now almost as swiftly as Nona, and with far less effort than I had used at first. * * * * * You are skeptical? Because _you_ cannot breathe your Earth-water, you assume that _I_ could not breathe this water on my meteor. What quaint logic that is! Yet I find all you Earth-people think on similar lines. It is your inadequate mentality, I suppose, so I must hasten to enlighten you. There are two fundamental objects of respiration. First: the introduction into the system of oxygen by which the products resulting from the disintegration of the muscular, nervous and other tissues of the body may be converted into compounds easily eliminated. Secondly: the direct removal of the most noxious and therefore most important of these waste products—carbonic acid gas. In man, as you know him on Earth, this is accomplished by the lungs. The venous blood, charged with its carbonic acid and its waste products, needing a renewal of oxygen and a removal of the carbonic acid, is pumped by the heart through the lungs. These by their construction present an immense amount of internal surface covered by a vascular network, through which the blood flows in innumerable minute streamlets. In respiration, the inhaled air is separated from the blood only by an extraordinarily thin membrane—less than 1/20,000 of an inch in thickness. Through this membrane the blood absorbs oxygen from the air, giving in return to the air its noxious carbonic acid gas. Such is the basic process in you Earth-men. In the case, let us say, of your Earth-fishes breathing your water, there is little fundamental difference. The blood in their gills is brought practically into contact with a steadily moving stream of water. But fishes do not get their oxygen from the water in some mysterious fashion. Did you think they did? They get the oxygen, not from water, but from air—the air that is held in solution in the water. But for two things, you on Earth could breathe your water. First, your lung passages are too minute to receive a substance so heavy, so _unvolatile_, let me say, as is the water of Earth. Secondly, there is not proportionally enough air in your water.