The first of the google book scans are available.
Things are rather meager, and most of the full-text downloadable .pdf files are from the 1850s. They're not full text, they're full images ... .gifs, or .pngs, or .jpgs, dunno which.
A lot of the books listed as "full text" aren't downloadable as whole .pdfs, but are only available online, tediously one page at a time. Those images render slowly. They should OCR (optical character recognize) the lot, they're going to do that anyway to serve their context-sensitive ads. Text would be rather faster to render, and a "clicky original image here" might help things along a bit.
The title doesn't always match the scanned work. As in, that Ohio'an medical reporter from 1873 is in fact "Proceedings of the Medical Convention of Ohio" from 1841... the next one with the same title is the Proceedings from 1849. Years matter, in old medical texts: the golden age of the eclectics started around 1870.
And there's skewed pages, "image not available", fingers, and all sorts of less than nice things in the scans.
It's a google beta. Thing is, google beta projects stay in beta for years on end, so it's not as if it'd be worth holding our collective breath for things to improve.
Which means I'll continue to add crosslinked classic herbal texts to my site, either my own scans or scans from Michael Moore (thanks Michael!) or Paul Bergner (thanks Paul!). Or those of others who send me their .rtf files to format and put up.
Here are the few worthwhile old works I've been able to dig up in google books:
Proceedings of the Medical Convention of Ohio: 1841, 1849.
Medical Communications of the Massachusetts Medical Society: 1841, 1860.
Transactions of the Ohio State Medical Society: 1853, 1857, 1859, 1860.
The American Medical Gazette and Journal of Health: 1858 (Jan-Dec 1857), 1861 (Jan-Dec 1860).
1852: John B Biddle: Review of Materia Medica for the use of students.
1854: Benjamin Ellis: The Medical Formulary. being a collection of prescriptions derived from the writings and practice of many of the most eminent physicians in America and Europe.
1855: Henry Beasley: The Book of Prescriptions. Containing 2900 prescriptions, collected from the practice of the most eminent physicians and surgeons, english and foreign.
1856: Henry Beasley: The Medical Formulary. Standard and approved formulae for the preparations and compounds used in medical practice.
1858: John King: Women: their diseases and their treatment.
1859: Martyn Paine: Materia Medica and Therapeutics.
1859: Edward Parrish: An introduction to Practical Pharmacy, designed as a textbook for the student. (1856)
1859: John W Comfort: The Practice of Medicine on Thomsonian Principles ... including ... a materia medica adapted to the work. (1853)
1861: John B Beck: Lectures on Materia Medica and Therapeutics. (1856)
I find the U Michigan downloadable OCR'd scans to be better, but alas, what's really needed is proofread text, or, if that's not possible, raw OCR + images side by side, in that downloadable file. The online version of the U Mich texts does give a choice of image, text or .pdf on each page. (There's some juicy stuff in there. Go for the making of america collection and search for "medica*" + author "King, John", for instance ... lovely.)