Page:Popular Science Monthly Volume 30.djvu/249

Rh in the approximately—if not for a time absolutely—stable mass of blood in the encephalic vessels as a whole, in the arrangement of the vessels themselves, and in the relation of their contents to the pressure of the atmosphere, we have conditions which contrast so remarkably with those we find in any other part of the body, that a consideration of their significance is surely deserving more attention from physiologists than it has yet received.—Brain.



F a blizzard of unusual severity were coming from the northwest that would send the thermometer down 50° or 70° in three hours, we should expect a great increase of pneumonia and other respiratory diseases, resulting in many deaths. Now, instead of three hours, suppose the mercury were to drop threescore degrees in three minutes—or take another step in fancy, and suppose this great change to take place in three seconds—what would likely be the effect on health? And yet we bring about, artificially, changes to ourselves quite as sudden and as severe as this.

We make an artificial climate in our houses. We live in-doors in an atmosphere heated by stoves, furnaces, or steam-pipes, to 70° or 80°; and we pass from our parlor or hall so heated into the open air. At a step, literally in a breath, the temperature of the air has, for us, dropped 50° or 70°. We may put on an extra coat or shawl and shield the outside of the body and chest, but we can not shield the delicate linings and membranes of the air-passages, the bronchial tubes, the lung-cells. Naked, they receive the full force of the change—the last breath at 70°, the next at freezing or zero—and all unprepared. We have been sitting, perhaps for hours, in a tropical atmosphere; nay, worse, in an atmosphere deprived by hot iron surfaces of its ozone and natural refreshing and bracing qualities. Our lungs are all relaxed, debilitated, unstrung; and in this condition the cold air strikes them perhaps 60° below what they are graduated to and prepared for. Is it strange if pneumonia and bronchitis are at hand?

If we are in the West Indies, or even in Florida, and wish to come North in winter, we try to make the change gradual. But in our houses we keep up a tropical climate, or worse, for you have not the freshness of air that prevails in an open tropical atmosphere, and we step at once into an atmosphere as much colder as 40° difference of latitude will make it. It is in effect going from Cuba to Iceland—or at least to New York—at a step, and we make the journey perhaps a dozen times a day. And often, while we are still shut up in our 