HELP!!!!!!

I'm doing a research paper about prison nursing, and I cannot find any information about when the first nurses were hired in prisons. I found that prior to the 1970's, health care in prisons was minimal. However, dates when nurese were actually hired into the system is impossible to find!! I have interviewed 3 people, telephoned and gone through zillions of articles and books and I still cannot find the answer! If anyone can help me I would greatly appreciate any advice or help.
Thank you.