Ranged damage not working

Below is my enemyHealth code

 using UnityEngine;
 using System.Collections;
 
 public class enemyHealth : MonoBehaviour 
 {
     public int maxHealth = 100;
     public float currHealth = 100;
 
     public float healthBarLength;
     
     
     
     // Use this for initialization
     void Start () {
         healthBarLength = Screen.width / 4;
     
     }
     // Update is called once per frame
     void Update () {
         AdjustCurrentHealth(0);
     }
     
     void OnGUI() {
         GUI.Box(new Rect(10, 40, healthBarLength , 20), currHealth + "/" + maxHealth);
     }
     public void AdjustCurrentHealth(int adj) {
         currHealth += adj;
         if(currHealth < 1)
             currHealth = 0;
         
         if(currHealth > maxHealth)
             currHealth = maxHealth;
         
         if(maxHealth < 1)
             maxHealth = 1;
         healthBarLength = (Screen.width / 4) * (currHealth / (float) maxHealth);
     }
 
 
     public void TakeDamage(int amount)
     {
         currHealth -= amount;
     }
 }

Below is my projectile code

using UnityEngine; using System.Collections;

 public class Projectile : MonoBehaviour
 {
 
     public int Damage;
     public GameObject target;
     public void OnCollisionEnter(Collision collision)
     {
     enemyHealth eh = (enemyHealth)target.GetComponent("enemyHealth");
     eh.AdjustCurrentHealth(- Damage);
     }
 }

I can't figure out what is wrong when I shoot them them their health doesnt decrease by 10 which is what i set the damage as.