Poisons

The scientist and assassin poison skill requires a syringe to use. The syringe must have some sort of poison in it to be useful. The commands for using a syringe are:

inject (victim) to poison someone.
empty syringe to empty the poison out of your syringe.
refill syringe to refill it from a bottle of poison.
check liquid to check the contents of the first syringe in your inventory.
check doses to check the number of doses left in the first syringe in your inventory.

There are several types of poisons, and the only way to know for sure what affect one of them will have is to try it out.