The ordinary appearance of perspiration in a healthy state is that of an oleaginous liquid consistency resembling, say, a thin cream; but the water exuded by the lungs has the appearance of dew, and is indeed called by a term signifying "lung-dew." It does not amalgamate with the oleaginous part of the perspiration. Our doctors at first thought that they could detect incipient consumption from the appearance of this dew, whilst they had only ascertained that the germs of some one of several diseases existed in the system. For although the presence of lung-dew in any quantity gives intimation that all is not right, the specific malady is not indicated with certainty. The application of certain tests to the patient is necessary to discover the particular disease with the incipient germs of which he is afflicted. Disease and contagion difficult to deal with in their advanced stages, when they have already made their presence known by symptoms too palpable to be disregarded, are easily mastered in their germ. To collect the perspiration, a little instrument, called "the scraper," is passed over the skin, and at each turn deposits the perspiration in an air-tight receptacle attached to the instrument. The blood was found to be but a partial test of disease, for there is much in the body which does not mingle with the blood, whilst the perspiration contains impurities thrown off by every part of the organization, and, when examined through our microscopes, never fails to give warning. At the same time the blood is the subject of deep study in Montalluyah; and every point connected with its component parts, colour, circulation, heat, quality, purification, is thoroughly understood. The physicians sometimes examine the breath. With this view, the patient breathes on a little instrument saturated with a preparation which condenses and retains the breath. Ample opportunity is thus afforded for its microscopic examination, and for the discovery of the unhealthy particles with which the breath may be impregnated. XV. MADNESS. "Think not others blind because ye will not see....The concentrated light of the soul is not visible to the naked eye." The microscope also led to the discovery of the incipient causes of madness, by the facility it afforded us for the dissection and examination of the minutest portions of the numerous divisions of the brain.