Medical journals from 19th-century British ships reveal that scorpion stings were treated at the time by pouring rum on the afflicted area. The same treatment applied to tarantula bites as well.
Even though alcohol is an effective antiseptic, in most cases it does not function as an antivenom. It is difficult to say whether physicians or first aid providers in the 1800s had easy access to 70 percent alcohol, but in hard conditions such as long ship voyages, shipmates would often have to improvise with whatever resources were available to them. Often a cloth or rubber band would be tied around the sting in order to stop the venom from spreading to other parts of the body.