Oberlin has a robust medical history collection from the early 20th century due to simply to the fact that our library collections supported college curriculum from that time period and we have done relatively little weeding since. To that we add digitized materials from other university colleges provided by JSTOR and HathiTrust. All of these materials can be accessed through Search.Libraries, using similar filters to the ones you would use for secondary research (e.g. Book/ebook, Scholarly & Peer Review), along with a publication date filter for the time period you are researching.
Read your secondary sources carefully to develop a pool of keywords you can use to search. Think particularly about terms that would have been used in scholarship from the time and which would be likely to appear in journal article or book titles.
You may encounter publications kept in the Oberlin "Storage" location as part of this research. To check these items out, simply log into your Search Libraries account and use the green "request" button on the item record to have the item delivered to the circulation desk at the Main Libraries. Be sure to leave a few days lead time for these requests to be filled.
It is unusual to get access to patient medical records created within the last century due to modern patient privacy laws. Wide distribution of any resources that could identify individual patients are only rarely available to professional researchers, often after hospital or archive staff have put significant time into anonymization.
As an example of this phenomena, Natalie Lira repeatedly cites a microfilm version of "Sterilization Records" from California's Department of Institutions, Department of Mental Hygiene in Laboratory of Deficiency. However, if you read the description of this collection in the California State Archives online catalog, you can see that access is restricted except to researchers who have filed a special access request with the state of California. It is unlikely that undergraduate students would be successful in such a request for any medical records that could identify patients who are still alive.