方法由于其保护级别而无法访问

我使用Unity3d和C#，我有两个脚本：

脚本1:

using UnityEngine;
using System.Collections;
public class PlayerAttack : MonoBehaviour {
    public GameObject target;
    // Update is called once per frame
    void Update () {
        if(Input.GetKeyUp(KeyCode.F))
        {
            Attack();
        }
    }
     void Attack() {
        EnemyHealth eh = (EnemyHealth)target.GetComponent("EnemyHealth");
        eh.HealthRulse(-10);
    }
}

脚本2:

using UnityEngine;
using System.Collections;
public class EnemyHealth : MonoBehaviour {
public int curHealth = 100;
public int maxHealth = 100;
public float healthBarLeangth;
    // Use this for initialization
    void Start () {
    healthBarLeangth = Screen.width / 2;
    }
    // Update is called once per frame
    void Update () {
         HealthRulse(0);
    }
    void OnGUI() {
        GUI.Box(new Rect(10,40,Screen.width / 2 / (maxHealth / curHealth),20),curHealth + "/" + maxHealth);
    }
    void HealthRulse(int adj){
        if ( curHealth < 0)
            curHealth = 0;
        if (curHealth > maxHealth)
            curHealth = maxHealth;
        if(maxHealth < 1)
            maxHealth = 1;
        curHealth += adj;
        healthBarLeangth = (Screen.width / 2) * (curHealth / (float)maxHealth);
    }
}

GetComponent在"脚本2"中定义并在"脚本1"中调用的函数"HeathRulse（）"引发错误-
"方法由于其保护级别而无法访问"

我需要帮助。。。