Unless the consignor accompanies the freight and retains exclusive control thereof, a common carrier of property is liable, from the time that he accepts until he relieves himself from liability as hereinafter provided, for the loss or injury thereof from any cause whatever, except:
1. An inherent defect, vice or weakness, or a spontaneous action, of the property itself.
2. The act of a public enemy of the United States, or of this state.
3. The act of the law; or,
4. Any irresistible superhuman cause.
R.L. 1910, § 815.