Like all successful politicians, Tony Blair understands and lives by the laws of the jungle.
The first of those laws states that the moment the dominant beast shows weakness, the pretenders circle, noses expectantly sniffing the air.
And if in his moment of weakness, the silverback gorilla or the lion king hesitates, his rule is brought to a swift and usually brutal end.
Blair won't want to show weakness
Politicians, in particular, know just how dangerous any sign of ill health can be.
That is why, in an earlier age when Britain had a docile, forelock-tugging media, scares over the health of figures including Churchill were hushed up.
Most recently, would-be Tory leader Michael Heseltine saw his leadership chances decline following heart problems when on holiday in Venice while he was a cabinet minister under John Major.
This was despite attempts - including an impromptu display of physical jerks from the next Tory party conference platform - to show he was fighting fit.
From the moment of his initial illness, almost always when his name was mentioned in any leadership context so was his heart problem. A subsequent post-1997 heart attack led to him announcing he would not be standing to succeed Mr Major.
Heseltine recovered - but his leadership ambitions did not
So the prime minister knows better than anyone just what he must do in the wake of his health scare.
He must demonstrate that this was no more than a minor, temporary illness which will have no lasting impact on his leadership.
And that will be bad news for those - friends and foes alike - hoping that it could mark the beginning of a less presidential style of leadership, that he will accept any doctors orders to take it easy or scale down his commitments.
Back to work
Tempting, and probably sensible as such advice might be, the danger is that it would be seen as another sign of weakness at a time when his leadership was already under greater strain than ever before.
If anything, there may be a new self-imposed pressure on Mr Blair to prove this setback has not affected his performance.
He has always been eager to demonstrate his fitness and youthfulness - even admitting in an interview with Saga magazine this year how he was "dreading" his 50th birthday.
Strains have been showing
So it is likely he will order his spokesmen to play down the scare and insist he has got back to business after only the briefest of breaks.
He will probably want to show publicly that he is in good health - and one opportunity to do that will come in his monthly press conference which is due any time now.
He will also make sure he still chairs any meeting already in his diary.
And, knowing Downing Street's addiction to spin, some sort of stunt cannot be ruled out. A Mao-style dip in the Thames, perhaps?
Whether any of this will actually stop the whispers and the speculation is highly doubtful.
This apparently minor incident may still have huge and lasting consequences.