“It came on him so suddenly,” he replied, “that we hadn’t much time to think.  As nearly as we could make out, it began with a faintness and difficulty in breathing.  We asked him how he felt—­ but it seemed as if he was deaf.  I thought it might be the ’bends’—­you know, caisson disease—­and we started to put him in the medical lock which we had for the divers, but before we could get it ready he was unconscious.  It was all so sudden that it stunned us.  I can’t make it out at all.”

Neither Asta nor Norma seemed able to tell anything.  In fact, the blow had been so swift and unexpected, so incomprehensible, that it had left them thoroughly alarmed.

The body of Traynor had already been brought ashore and placed in a local undertaking shop.  With Everson, Kennedy and I hastened to visit it.

Traynor had been an athlete and powerfully built, which made his sudden death seem all the more strange.  Without a word, Craig set to work immediately examining his body, while we stood aside, watching him in anxious silence.  Kennedy consumed the greater part of the morning in his careful investigation, and after some time Everson began to get restless, wondering how his wife and sister-in-law were getting on in his absence.  To keep him company I returned to the hotel with him, leaving Kennedy to pursue his work alone.

There was nothing much that either of us could say or do, but I thought I observed, on closer acquaintance with Norma, that she had something weighing on her mind.  Was it a suspicion of which she had not told us?  Evidently she was not prepared to say anything yet, but I determined, rather than try to quiz her, to tell Kennedy, in the hope that she might confide in him what she would not breathe to any one else.

It was perhaps an hour or more later that we returned to Craig.  He was still at work, though from his manner it was evident that his investigations had begun to show something, however slight.

“Have you found anything?” asked Everson, eagerly.

“I think I have,” returned Craig, measuring his words carefully.  “Of course you know the dangers of diving and the view now accepted regarding the rapid effervescence of the gases which are absorbed in the body fluids during exposure to pressure.  I think you know that experiment has proved that when the pressure is suddenly relieved the gas is liberated in bubbles within the body.  That is what seems to do the harm.  His symptoms, as you described them, seemed to indicate that.  It is like charged water in a bottle.  Take out the cork and the gas inside which has been under pressure bubbles up.  In the human body, air and particularly the nitrogen in the air, literally form death bubbles.”

Everson said nothing as he regarded Kennedy’s face searchingly, and Craig went on:  “Set free in the spinal cord, for instance, such bubbles may cause partial paralysis, or in the heart may lead to stoppage of the circulation.  In this case I am quite sure that what I have found indicates air in the arteries, the heart, and the blood vessels of the brain.  It must have been a case of air embolism, insufflation.”