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which have been called the jewels of knowledge; in principles, the golden threads upon which they are hung.
Of all sciences, the greatest advance has perhaps been made of late years in chemistry and physics, and in its turn physiology has reaped abundantly the fruits of their labours.
Chemistry has always been a true friend to medicine: at first in the humble guise of a slave, wholly devoted to the discovery of some "aurum potabile," or elixir of life, which should bestow immortality and boundless wealth upon their possessor; but now as a mighty ally who permits a few only of her followers to search for the "Arcana" of the Kingdom of Life.
Until the last few years, however, chemistry has been mainly occupied with the production of what were called inorganic compounds, and with the analysis or breaking up of organic substances. It could not produce any of the myriad combinations which were constantly formed by the simplest animal or vegetable structures. By many, therefore, these organic bodies were looked upon as things apart, not to be put together by the unhallowed hand of the chemist, only to be brought into being when touched by the sacred Promethean flame of life.
At the present time the aspect of the field of chemical research is quite altered. It is true that the analysis of complex substances is not neglected. The tar products alone number many hundred, and include many bodies useful, not only in manufactures, but also in medicine. But the synthesis, or building up of new combinations formerly supposed to be the appanage of organized beings, is now going forward in most of the chief laboratories of chemistry.
A few years ago Wöhler broke the charm which was supposed to hedge round organic bodies, and commenced the great work of synthesis by producing urea, before then a product of animal life only.
