"Venerable Sir (Bhante), a certain monk at Savatthi has died after being bitten by a snake."
"Assuredly, monks," the Buddha replied, "that monk has not suffused with thoughts of loving-kindness (metta) the four royal tribes [families] of snakes.
"Monks, that monk did not suffuse with thoughts of loving-kindness these four royal tribes of snakes. Had he done so, he would certainly not have died of snakebite!
"Monks, I enjoin you to suffuse with thoughts of loving-kindness these four royal tribes of snakes for your safety, for your preservation, and for your protection."
Thus spoke the Blessed One. Having thus spoken, the Buddha, the "Welcome One" (Sugata), further said (suggesting how one should express oneself):
May I have metta towards Virupakkhas.
Towards Erapathas may I have metta.
May my metta be towards Chabyaputtas.
Towards Kanhagotamakas also metta may I have.
May I have metta towards the footless.
And towards bipeds too, metta may I have.
May I have metta towards quadrupeds.
And towards the many-footed also metta may I have.
Let not the footless do me harm
Nor those that have two feet.
Let not quadrupeds do me harm
Nor those endowed with many feet.
All beings, all living creatures,
May good fortune befall them all!
May not the least harm on them fall.
Boundless [in terms of virtue] is the Buddha. Boundless is the Dharma. Boundless is the Sangha [the community of accomplished practitioners].
Limited are creeping creatures -- snakes, scorpions, centipedes, spiders, lizards, and rats. I have guarded myself. I have made my protection. Depart from me, such beings.
I salute the Blessed One and to the seven supreme buddhas.**
*Khandha Paritta from The Book of Protection (Ven. Piyadassi translation, WQ edit) of the Cula Vagga, ii. p. 110; also in the Anguttara Nikaya under the title Ahi (Metta) Sutta, ii.72; Khandha-Vatta Jataka, 203.
** Seven supreme buddhas (in chronological order): Vipassi, Sikhi, Vessabhu, Kakusanda, Konagama, Kassapa, and Gotama.
Snakebite Science (Wikipedia edit)
Most snakebites are caused by non-venomous snakes. Of the roughly 3,000 known species of snake found worldwide, only 15% are considered dangerous to humans. Snakes are found on every continent except Antarctica.
The most diverse and widely distributed snake family, the Colubrids, has only a few members that are harmful to humans. Of the 120 known indigenous snake species in North America, only 20 are venomous to human beings, all belonging to the families Viperidae and Elapidae. However, in the United States, every state except Maine, Alaska, and Hawaii is home to at least one of 20 venomous snake species.
Since the act of delivering venom is completely voluntary, all venomous snakes are capable of biting without injecting venom into their victim. Such snakes will often deliver such a "dry bite" (about 50% of the time) rather than waste their venom on a creature too large for them to eat.
Some dry bites may also be the result of imprecise timing on the snake's part, as venom may be prematurely released before the fangs have penetrated the victim’s flesh. Even without venom, some snakes, particularly large constrictors such as those belonging to the Boidae and Pythonidae families, can deliver damaging bites.
Large specimens often cause severe lacerations as the victim or the snake itself pulls away, causing the flesh to be torn by the needle-sharp recurved teeth embedded in the victim. While not normally as life-threatening as a bite from a venomous species, the bite can be at least temporarily debilitating and as mentioned below, could lead to dangerous infections if improperly treated.
While most snakes must open their mouths wide before biting the victim, one type of African snake, the stiletto snake, can stab its victim from the side with its mouth closed. Another can spit blinding poison from a distance.