In The Journal of last week attention was directed to the reprint edition of Dr. Charles Denison's paper on the " Preferable Climate for Phthisis," read in the Section of Demography of the Ninth International Medical Congress, Washington, 1887. Attention was then directed to the chief elements that, in varying combinations, determine the special character of the climate in any given locality. The combination of these elements claimed by Dr. Denison as constituting the preferable climate for patients affected with phthisis is, purity, rarefaction, dryness, coolness, variability, uneven or mountainous surfaces, with gravelly or porous soil. The purity of the atmosphere or freedom from intermixture with foreign ingredients increases with the altitude above the sea level, and according to the observations of Miquel, becomes entirely free from bacteria or organic germs at an elevation above 2,000 metres (ft. 6,560). At 560 metres (ft. 1,700) he found only 8 bacteria to 10