48 HEALTHY AND UNHEALTHY RESIDENCES. 



surface; hence it is not breathed unless a person lies close to the 

 ground. 



On the other hand, heat so rarefies the malaria as to make it 

 comparatively harmless. 



The coldness of night condenses and renders the malaria heavy, 

 and, therefore, it is thrown to the surface of the ground, while the 

 heat of the day rarefies it, and sends it upward toward the clouds 

 again. From these facts it is readily perceived why country people, 

 going to town, as they did in the day-time, could do so with com- 

 parative safety. The effect of the sun -light also is to enhance the 

 purifying process. 



Not more than half a century ago, the yellow fever and other 

 deadly diseases prevailed in Charleston, South Carolina, and it was 

 known at the time to be almost certain death, except to the accli- 

 mated, or to the very hardy, to sleep in the city a single night. Yet 

 the farmers came to town at mid day, under the blistering summer 

 sun, with perfect impunity. 



Location of Bed-Chambers From June to October, peo- 

 ple should sleep in the upper stories of their dwellings. And the 

 rooms should be so situated that the rays of the sun can be admitted 

 into them some time during the day. There is an Italian adage, to 

 the effect that, " Where the sun does not enter, the doctor does." 



When Malaria Does its Destructive Work Malaria 

 is most pernicious about sunset and sunrise, because the cooling of 

 the atmosphere, at the close of the day, causes it to become con- 

 densed above, and therefore heavy, and to fall to the earth ; while, after 

 sundown, it has settled so near to the earth as to be below the mouth 

 and nostrils; hence it is not breathed. Another reason is that the 

 bodily vitality is lowered during the night, and thus we have a 

 smaller resisting power between sunset and sunrise. When the sun 

 begins to rise in the morning, the malaria grows warm and begins 

 to ascend ; but after breakfast it is so high as to be above the point 

 at which it can be breathed; and besides, it is so rarefied so widely 

 diffused as to be innocuous or harmless. Therefore, the practical 

 truth follows, that malaria exerts its most baleful influence on human 

 health about sunrise and sunset; hence, of all the hours of the 

 twenty-four, these are the most hurtful in which to be out of doors; 

 and for the same reason, the hours of midday and midnight are the 

 most healthful to be in the open air in malarious seasons; that is, 

 from June to October, north of the thirty -fifth degree of north lati- 

 tude. 



How to Render Malaria Harmless But, unfortun- 

 ately, Ae cool of the early morning and the late afternoon are the 

 most pleasant times in the twenty-four hours for field-work, and 

 the industrious farmer will be exceedingly loth to spend these 

 hours in-doors. There is, however, an almost infallible preventive 

 of any ill effects arising from such an exposure to miasm, or mal- 

 aria, about sunrise or sunset j and it ought to be made known 



