The practice that expert testimony does not have legal effect until it is affixed with an official seal has correspondin摘要鉴定文书加盖公章才具有法律效力，具有相应的法律依据，它在表明鉴定主体合法性、鉴定文书制作程序规范性和鉴定结论的可采性方面具有重要意义。