It is written, "Man shall not live by bread alone,
but by every word that proceeds from the
mouth of God."
From the Vivekacudamani
Commentary by Sri Candrasekhara Bharati of Sringeri
The poison of a king cobra can bring about the death of a person. But more fatal than that are the sense-objects which are more virulent. If a person is bitten in the leg or any other part of the body by a king cobra, the poison quickly travels thence to the tongue through the blood vessels mixing with the blood in them. Hence the expression bhokta (swallows). That is why in some cases, though bitten by a cobra on the leg, if a tight bandage is made at the spot, man does not die: because there is no connection of that poison with the tongue through the nadis. Thus, the poison kills a man who is affected internally by it; i.e., it makes him non-existent.
But, this poison of the sense-objects kills him who merely perceives it. For it is well known that men quarrel among themselves when they perceive beautiful objects etc., and die as a result. Even though there is no quarrel, their minds being enticed by those objects, they are disabled to realise their atman; they are rendered incapable of perceiving the effulgence of their own atman. So nihanti here means either being as good as non-existent or not being effulgent and so not known. The meaning is to be adopted according to the context. Whatever is non-existent will not be effulgent; will not be known.
In fact, a person attached to sense-objects, though he is existent, will not attain his proper objective of moksa. So, he is as good as non-existent.
The Poison That Kills
Apart from sense-experience
being a cause of death,
the sense objects kill when you
simply see them and, as such,
they are more deadly than the
poison of a king cobra.
That is stated in this sloka #79:
"Dosena tivro visayah krsnasarpavisadapi
visam nihanti bhoktaram drastaram
"A sense-object is more virulent
than the poison of a king cobra.
The latter kills only him who swallows it;
the former brings about death
of him who merely looks at it."