Shooting and health Help

I'm using raycast for my fps and I don't know how to send the message to the enemy when he is hit. here is my shooting script

 var bulletSpeed: float = 1000; // bullet speed in meters/second
   var shotSound: AudioClip;
   function Update(){
     if(Input.GetMouseButton){
       Fire();
     }
   }
 
   function Fire(){
     if (audio) audio.PlayOneShot(shotSound); // the sound plays immediately
     var hit: RaycastHit; // do the exploratory raycast first:
     if (Physics.Raycast(transform.position, transform.forward, hit)){
       var delay = hit.distance / bulletSpeed; // calculate the flight time
       var hitPt = hit.point;
       hitPt.y -= delay * 9.8; // calculate the bullet drop at the target
       var dir = hitPt - transform.position; // use this to modify the shot direction
       yield WaitForSeconds(delay); // wait for the flight time
       // then do the actual shooting:
       if (Physics.Raycast(transform.position, dir, hit)){
        //need it here!!!
       }
     }
    }
 

So what will I need to add to my script and what will I need to give to my enemy