Before revoking any license the Department of Health and Social Services shall give written notice to the licensee affected, stating that it contemplates the revocation of the same and giving its reason therefor. The notice shall appoint a time of hearing before the Department of Health and Social Services or its deputies, and shall be mailed by registered mail to the licensee. On the day of hearing the licensee may present such evidence to the Department of Health and Social Services as the licensee deems fit, and after hearing all the testimony, the Department of Health and Social Services shall decide the question in such a manner as to it appears just and right.