Plants also played a very important role, and the herb-doctors devoted endless labor to searching for such plants.
Thus the blood-root, with its red juice, was supposed to be useful in blood diseases, in stopping hemorrhage, or in subduing the redness of an inflammation.
Paracelsus's system of signatures, however, was so complicated by his theories of astronomy and alchemy that it is practically beyond comprehension.

It is possible that he himself may have understood it, but it is improbable that any one else did--as shown by the endless discussions that have taken place about it.

But with all the vagaries of his theories he was still rational in his applications, and he attacked to good purpose the complicated "shot-gun" prescriptions of his contemporaries, advocating more simple methods of treatment.
The ever-fascinating subject of electricity, or, more specifically, "magnetism," found great favor with him, and with properly adjusted magnets he claimed to be able to cure many diseases.

In epilepsy and lockjaw, for example, one had but to fasten magnets to the four extremities of the body, and then, "when the proper medicines were given," the cure would be effected.

The easy loop-hole for excusing failure on the ground of improper medicines is obvious, but Paracelsus declares that this one prescription is of more value than "all the humoralists have ever written or taught." Since Paracelsus condemned the study of anatomy as useless, he quite naturally regarded surgery in the same light.