Here is a medical website talking about snake bite. I extracted some text regard not cutting or using a turnaquet.

http://www.emedicinehealth.com/snakebite/page5_em.htm

A number of old first aid techniques have fallen out of favor. Medical research supports the following warnings:

Do NOT cut and suck. Cutting into the bite site can damage underlying organs, increase the risk of infection, and does not result in venom removal.

Do NOT use ice. Ice does not deactivate the venom and can cause frostbite.

Do NOT use electric shocks. The shocks are not effective and could cause burns or electrical problems to the heart.

Do NOT use alcohol. Alcohol may deaden the pain, but it also makes the local blood vessels bigger, which can increase venom absorption.

Do NOT use tourniquets or constriction bands. These have not been proven effective, may cause increased tissue damage, and could cost the victim a limb.