It is sometimes held that the real originator of the theory of signatures, in any approximation to a scientific form, was Giambattista Porta, who was probably born at Naples shortly before the death of Paracelsus. He wrote a book about human physiognomy, in which he endeavoured to find, in the bodily form of man, indications as to his character and spiritual qualities. This study suggested to him the idea that the inner qualities, and the healing powers of the herbs might also be revealed by external signs, and thus led to his famous work, the ‘Phytognomonica,’ which was first published at Naples in 1588. Porta developed his theory in detail, and pushed it to great lengths. He supposed, for example, that long-lived plants would lengthen a man’s life, while short-lived plants would abbreviate it. He held that herbs with a yellow sap would cure jaundice, while those whose surface was rough to the touch would heal those diseases that destroy the natural smoothness of the skin. The resemblance of certain plants to certain animals opened to Porta a vast field of dogmatism on a basis of conjecture. Plants with flowers shaped like butterflies would, he supposed, cure the bites of insects, while those whose roots or fruits had a jointed appearance, and thus remotely suggested a scorpion, must necessarily be sovereign remedies for the sting of that creature. Porta also detected many obscure points of resemblance between the flowers and fruits of certain plants, and the limbs and organs of certain animals. In such cases of resemblance he held that an investigation of the temperament of the animal in question would determine what kind of disease the plant was intended to cure. It will be recognised from these examples that the doctrine of signatures was remarkably elastic, and was not fettered by any rigid consistency. [Illustration: Text-fig. 109. Herbs of the Scorpion [Porta, Phytognomonica, 1591].] The illustrations of the ‘Phytognomonica’ are of great interest as interpreting Porta’s point of view. The part of man’s body which is healed by a particular herb, or the animal whose bites or stings can be cured by it, are represented in the same wood-cut as the herb. For example, the back view of a human head with a thick crop of hair is introduced into the block with the Maidenhair Fern, which is an ancient specific for baldness; a Pomegranate with its seeds exposed, and a plant of “Toothwort,” with its hard, white scale-leaves, are represented in the same figure as a set of human teeth; a drawing of a scorpion accompanies some pictures of plants with articulated seed-vessels (Text-fig. 109) and an adder’s head is introduced below the drawing of the plant known as the “Adder’s tongue.”