While legal writers and practitioners alike have often used these terms indiscriminately, as synonymous with each other, each has a well-defined meaning in the law. The most careful logicians have applied the term "evidence" to the medium by which the truth is established, and the term "proof' to the effect which the evidence produces upon the judicial mind. "Evidence" bears the same relation to "proof' that "cause" does to "effect"; i. e., a means to an end. Proof is the end to be attained; evidence the means of attaining it.