Microtome
en.wikipedia.org
en.wikipedia.org
Microtomes are also useful in surgeries. A subzero version of it called a cryostat is often used to get rapid diagnostic information. Tissue is sent to the anatomic pathology lab mid-surgery to obtain critical information (e.g., is the surgical margin of this tumor resection free of tumor cells? What is this lump of tissue incidently found on the pancreas?).
We would take the tissue, throw some green ink on it, cut it into a small piece, then rapidly freeze it by putting it in a goopy liquid medium that rapidly solidifies in the subzero ambient environment of the cryostat. Then we’d use the built in microtome which is at the same subzero temperature to cut the frozen block of goop and tissue and get a nice 10ish micron section on a glass slide. Getting the tissue on the slide correctly required a highly specialized tool to guide the tissue slice to the glass (a fine $1 paint brush held at the same temperature). Dip the glass slide into alcohol then throw some colorful stains on it and we can look at it under the microscope and determine if the surgeon needs to take more (we see that green ink) or if that unknown lesion he found is a benign growth or metastatic melanoma. Takes about 20 minutes, all done while the patient is still under anesthesia and has an open surgical site.
He says you had to break a glass blank to get a good cutting edge. He apparently was often given the task of breaking the glass because he seemed to get better knives.
I believe he said the mechanism that was used to advance the sample into the knife to cut the sample/slice involved a long metal bar where heat was dialed up to make the bar expand in length — that amount of expansion being the thickness of the slice they were after.