SYSTEMATIC SYNTHESIS OP ORGANS INTO APP. 387 



1253. Inf. The evil can always be avoided by sufficient attention 

 to cleanliness and ventilation, especially of the bed-clothing. 



1254. IF THE SAME BEEATH IS AGAIN INHALED, the 



oxygen is diminished, and the carbonic acid and other 

 impurities increased still further, but in smaller propor- 

 tions, while the moisture remains the same. 



1255. Inf. THE SAME AIR SHOULD NEVER BE INHALED A SECOND 

 TIME, since it can neither yield the appropriate oxygen to the Blood, 

 nor extract from it the noxious carbonic acid. 



1256. Inf. WHATEVER DIMINISHES THE OXYGEN of the air, or in- 

 creases its carbonic acid, makes it unhealthy. 



1257. Him. Charcoal burning in a room has often destroyed life; 

 so has a candle in a small room : gas, or anything burning in an un- 

 ventilated apartment, diminishes the oxygen and increases the carbonic 

 acid. 



1258. Remark. ALLOWANCE MUST ALWAYS BE MADE in ventilating 

 apartments in which anything is burned. To heat rooms with gas with- 

 out ventilation is very unhealthy. 



1259. MOISTURE is always an essential part of the 

 atmosphere, and should exist nearly to saturation. 



1260. WHEN ROOMS ARE HEATED ARTIFICIALLY, 

 moisture should be evaporated into the air, or it will be 

 so dry as to exhaust too much moisture from the lungs. 



1261. Remark. DAMP AIR is often thought to be injurious to the 

 lungs, and cold dry air is welcomed as wholesome. It is not, however, 

 dry to the lungs ; its frost melts and saturates the air ere it enters the 

 lungs. Dampness, if cold, is not obnoxious to the lungs, but it is to a 

 thinly-clad skin. The electric condition of the air has more to do with 

 its uncomfortableness than its dampness. When the air is positively 

 electric, though warm or cold, it will be bracing and refreshing, while 

 if negatively electric, it will be oppressive and unhealthy. These influ- 

 ences are by some attributed to the presence or absence of ozone, a con- 

 dition of oxygen. But is not that owing to electric action ? One thing 

 is certain ; air that has swept over ice, and become positively electric, 

 produces a more invigorating effect than can be accounted for by its 

 purity or temperature. The northwest wind in summer comes out from 

 the great polar ice-box bearing healing on its wings and strengthening 

 the well. Rooms ventilated in summer with air passed over ice are not 



1253. How ? 1254. What ? 1255. Should ? 1256. Inf. 125T. Illus. 

 1253 For what-? 1259. What said of-? 1260. What said ? 1261. What said of-? 



