Ages of spirituality have preceded the past age of materiality, and other eras of higher spiritual thought are certain to follow. During these preceding ages many eminently valuable truths were known, which have been lost sight of in modern times, and although the popular science of the present, which deals with the external appearances of physical nature, is undoubtedly greater than that of former times, a study of the ancient books on medicine shows that the sages of former times knew more of the fundamental laws of nature than what is admitted to-day. There is a great science and a little science; one that flies around the spires of the temple of wisdom, another that penetrates into the sanctuary; both are right in their places; but the one is superficial and popular, the other profound and mysterious; the one makes a great deal of clamour and show, the other is silent and not publicly known. There are progressive and there are conservative scientists. There are those whose genius carries them forward and who dare to explore new realms of knowledge; while the conservative class merely collects what has been produced by others. An explorer must be a scientist; but not every scientist is an explorer. The majority of our modern schools of medicine produce nothing new, but merely deal in goods in whose production they had no share. They resemble the shop of a huckster who knows nothing else but the goods which are in his shop. The shelves are filled with popular theories, fashionable beliefs, patented systems, and occasionally we find an old article that went out of fashion, labelled with a new name and advertised as something new, and the proprietor volubly praises his goods, being as proud of them as if he had made them himself, while he ignores or denounces everything that is not to be found in his shop. But the real lover of truth is not contented to live upon the fruits that have grown in the gardens of others; he gathers the materials he finds, not merely for the purpose of enjoying their possession, but for the purpose of using them as steps to ascend nearer to the fountain of eternal truth. The present work is an attempt to call the attention of those who follow the profession of medicine to this higher aspect of science and to certain forgotten treasures of the past, of which an abundance may be found in the works of Theophrastus Paracelsus. Many of the ideas advanced therein, old as they are, will appear new and strange; for everyone is familiar only with that which is within his own mental horizon and which he is capable of grasping. The subject treated is so grand, unlimited and sublime, as to render it impossible in a limited work of this kind to deal with it in an exhaustive manner; but we hope that what little has been collected in the following pages will be sufficient to indicate the way to the acquisition of that higher mystic science, and to a better understanding of the true constitution of man.