You have probably all used JSTOR at one time or another to get access to online journals. What you might not realize is that JSTOR is part of ITHAKA, a not-for-profit organization helping the academic community use digital technologies to preserve the scholarly record and to advance research and teaching in sustainable ways.
JSTOR is currently collaborating with The Royal Society to digitize, preserve, and extend access to their Philosophical Transactions back to 1685. So, for example, you can now read the first journal report on the medicinal powers of willow bark (now known to be due to high concentrations of salicyclic acid - closely related to the active ingredient in aspirin.) Salicyclic acid is now known to be an important compound in mediating what is known as 'systemic acquired resistance' in plants - the plant equivalent to the innate immune system found in animals.
At this time in human history the 'doctrine of signatures' was still widely believed - that a plant shaped like a body part or disease would be useful in curing it (hence the names liverwort, woundwort, toothwort, wormwood etc). This was a theological reasoning rather than a scientific observation - it was reasoned that the Almighty must have set his sign upon the various means of curing disease which he provided. Through time this concept was expanded so that the "signature" could also be identified in the environments or specific sites in which plants grew.
Hence the following passage:
'As this tree delights in a moift and wet foil, where agues chiefly abound, the general maxim, that many natural remedies carry their cure along with them, or their remedies lie not far from their caufes, was fo very appofite to this particular cafe, that I could not help applying it; and that this might be the intention of Providence, I muft own had fome little weight with me.'