Here's a really interesting excerpt from a medical book called Sefer Refuos (ha-nikra) Ezer Yisrael, which was printed in 1790.
This book was written by a Jewish physician named Moses Marcuse. The point of it was to teach the masses proper hygiene and health concepts in accordance with the best 18th century medical knowledge, which was not as bad as it sounds. He instructs, pleads and cajoles with people to be aware of the issues, to keep clean, get fresh air, avoid witches and baalei shem, and other charlatans (bleigiessen, which people somehow still believe in, makes a starring appearance). He has harsh words for these people whom he holds responsible for murder - murdering their patients by their lack of knowledge and ineptitude. He calls them "memitim." Doctors who kill. As indicated by the title, it is not only an "ezer yisrael," "help[ful] for Jews," but a "sefer refuos," a book full of remedies for various ailments.
It was written in Yiddish rather than Hebrew so that it could be understood by more people (in this time virtually the only books written in Yiddish were moralistic or novels). Interestingly, he writes in the book that the reason why he chose to write in Yiddish was at the urging of none other than R. Rafael Kohen Hamburger, the rabbi of Altona-Hamburg-Wandsbeck, telling him that there are already plenty of scientific and medical works in Hebrew, but the people need one in Yiddish.
Also of interest - on the title page he calls the language the book is written in Polishtaytsch, meaning the "German spoken by the Polish Jews." He gives his name as Moshe hanikra Marcuze Doktor. In the seven or eight haskamos he is "Moshe ben mhr"r Mordechai" which is to be expected, as Marcuse is clearly some variant of Marcus, which was a common kinnuy for Mordechai.
The book deserves its own post, and will get one. But here is the passage where he decries fake doctors who wear "half-beardelach" (to impress the people with their physician-like look, but don't want to shave it all off, so the people will think they are pious) and who chant "hocus pocus " so that the people think they know Latin! Now I don't really know what the third word is; it says "Ocus Bocus Taryocus? Triyocus?" I wasn't able to identify this pseudo-Latin word, or the words which follow.
Marcuse was from Koenigsberg, or so he claimed. While he undoubtedly lived in Lithuania and other parts of Poland, there seem to be some indications that he was actually a "Polish" Jew himself, not Prussian, as would have readers believe. In any case, Hocus Pocus!