with the size and rank in creation of the animal, would be a problem well worthy of solution. Experiments of this kind upon any scale might be instituted in the Zoological Gardens, where the moping owl and ivy-mantled tower might be associated. In one of my own houses, about ten feet square, which was filled with small Palms, and sufficiently close for the growth of the most delicate ferns, a robin lived for several months, at the end of which time he escaped in consequence of the accidental opening of the door. Among the diseases incident to man, which would be most materially benefited by pure air, I shall allude only to two, viz.—measles and consumption. This is not the place to enter into any long discussion on medical points; but, believing firmly as I do that a properly regulated atmosphere is of more importance in these diseases than all other remedial means, it would have been unpardonable in a work like the present to have passed them over without notice. In the crowded districts of large towns the direct mortality arising from measles is always great, but nothing I believe compared with the numbers that die at various and distant intervals in consequence of neglect during the disease. Nearly all this distress and mortality might be averted were there proper rooms provided for the reception of the children of the poor when labouring under this complaint, or even of communicating it in favorable seasons. With respect to consumption, could we have such a place of refuge as I believe one of these closed houses would prove to be, we should then be no longer under the painful necessity of sending a beloved relative to a distant land for the remote chance of recovery, or too probably to realize the painful description of Blackwood: "Far away from home, with strangers around him,—a language he does not understand,-doctors in whom he has no confidence,-scenery he is too ill to admire, religious comforters in whom he has no faith,with a deep and every day more vivid recollection of domestic scenes,-heart-broken, -home-sick,-friendless and uncared for, he dies." In concluding my little work I feel that apologies are due for its many imperfections. The unremitting toil of general medical practice allows of little time for scientific enquiries; and I shall be satisfied if the facts which have been stated, and the hints which have been thrown out, excite the attention of those who possess more knowledge, time and means, than myself. Deeply convinced of the great practical utility and high importance of these researches, I hope yet to see the day when, in our universities and great public schools, the study of Natural History will be deemed at least as worthy of attention as an ode of Pindar, or a proposition of Euclid; and the students no longer presented "with an universal blank Of Nature's works, to them expunged and rased, APPENDIX. (A) Copy of a Letter to DAVID DON, Esq., read before the Linnean Society of London, June 4th, 1833. My Dear Sir, Wellclose Square, June 4, 1833. The difficulty of conveying ferns from foreign countries has long been matter of regret to the cultivators of that most interesting family of plants. About three years ago I was led to make some experiments upon the subject, in consequence of noticing a seedling of Aspidium Filix-mas, and one of Poa annua, on the surface of some moist mould in a large bottle, in which I had buried the chrysalis of a Sphinx. Curious to observe how vegetation would proceed in so confined a situation, I placed the bottle, loosely covered with a tin lid, outside one of my windows, with a northern aspect. This cover allowed a sufficient change of air for the preservation and development of the plants, and, at the same time, prevented the |