Pathologically considered, the use of perfumes is in the highest degree prophylactic; the refreshing qualities of the citrine odors to an invalid is well known. Health has often been restored when life and death trembled in the balance, by the mere sprinkling of essence of cedrat in a sick chamber. The commercial value of flowers is of no mean importance to the wealth of nations. But, vast as is the consumption of perfumes by the people under the rule of the British Empire, little has been done in England towards the establishment of flower-farms, or the production of the raw odorous substances in demand by the manufacturing perfumers of Britain; consequently nearly the whole are the produce of foreign countries. However, I have every hope that ere long the subject will attract the attention of the Society of Arts, and favorable results will doubtless follow. Much of the waste land in England, and especially in Ireland, could be very profitably employed if cultivated with odor-bearing plants. The climate of some of the British colonies especially fits them for the production of odors from flowers that require elevated temperature to bring them to perfection. But for the lamented death of Mr. Charles Piesse,[A] Colonial Secretary for Western Australia, I have every reason to believe that flower-farms would have been established in that colony long ere the publication of this work. Though thus personally frustrated in adapting a new and useful description of labor to British enterprise, I am no less sanguine of the final result in other hands. Mr. Kemble, of Jamaica, has recently sent to England some fine samples of Oil of Behn. The Moringa, from which it is produced, has been successfully cultivated by him. The Oil of Behn, being a perfectly inodorous fat oil, is a valuable agent for extracting the odors of flowers by the maceration process. At no distant period I hope to see, either at the Crystal Palace, Sydenham, at the Royal Botanical Gardens, Kew, or elsewhere, a place to illustrate the commercial use of flowers--eye-lectures on the methods of obtaining the odors of plants and their various uses. The horticulturists of England, being generally unacquainted with the methods of economizing the scents from the flowers they cultivate, entirely lose what would be a very profitable source of income. For many ages copper ore was thrown over the cliffs into the sea by the Cornish miners working the tin streams; how much wealth was thus cast away by ignorance we know not, but there is a perfect parallel between the old miners and the modern gardeners. Many readers of the "Gardeners' Chronicle" and of the "Annals of Pharmacy and Chemistry" will recognize in the following pages much matter that has already passed under their eyes. To be of the service intended, such matter must however have a book form; I have therefore collected from the above-mentioned periodicals all that I considered might be useful to the reader.