ATMOSPHERE IN RELATION TO HUMAN LIFE AND HEALTH. 245 



skin actually and normally emit in good health living microorganisms, 

 either pathogenic or harmless, but the probability is considerable when 

 we remember that the mouth and air passages are inhabited by various 

 species, and that warm evaporating surfaces exercise a repulsive force 

 on minute particles. Foster states that the aqueous product from the 

 breath is very apt to putrefy rapidly, owing to the presence of micro- 

 organisms. It is not generally assumed, however, that living microbes 

 are exhaled to an appreciable extent. The subject is an important 

 one and demands inquiry, but the ultra microscopic minuteness of the 

 germs may defeat direct observation. As to the frequent emission of a 

 deadly x^artieulate poison, however, no doubt whatever can exist. 1 It 

 is a dangerous and pernicious element in all aggregations, and, com- 

 bined with carbon dioxide, produces, when in moderate quantity, depres- 

 sion, headache, sickness, and other ailments; when in large quantity, 

 as in the Black Hole of Calcutta, and in various prisons of which there 

 is record, rapid death in the majority and fever in the survivors. Its 

 action upon the development of living germs when deposited upon 

 outside objects has not been ascertained. Probably it may be favor- 

 able to some and unfavorable to others. Some of the most deadly 

 human and animal diseases certainly are capable of virulent growth in 

 their presence, and of passing' more easily in a potent condition through 

 air in which they are abnormally concentrated. 



ORGANIC EMANATIONS PROM THE SICK. 



Hospitals, when not well ventilated, contain a very large quantity of 

 organic matter floating in the air and deposited on walls and floors. 

 This gives rise, in the most impure air, to hospital gangrene and ery- 

 sipelas, increases the severity of many diseases, and prolongs conva- 

 lescence. Gangrene having once appeared, is very difficult to get rid 

 of. Thorough ventilation and hygiene of the building where the sick 

 are received and treated prevents these evils from arising. 



ORGANIC EMANATIONS FROM THE SKIN. 



Sweat contains salt, lactate, butyrate, and acetate of ammonium; cal- 

 cic phosphate, ferric oxide, volatile fatty acids, e. g., sometimes valeri- 

 anic and caproic acid, and sometimes leucin. Perspiration gives off 

 into the air a large quantity of vapor, about 2 pounds in tlie twenty- 

 four hours and a little over 1 per cent of this quantity of solid organic 

 matter. Patty acids, inorganic salts, neutral salts, ammonia, and par- 

 ticles of epidermis are constantly passing from the skin into the air. 

 In the sick the matter emanating from the skin is often largely 

 increased and is very offensive. 



1 Some recent experiments of Smith and Haldane seem to show that carbon dioxide 

 is the only element of mischief, but the conditions of ordinary life are so various and 

 so difficult to imitate in experimental investigation that the inquiry needs to be 

 widely extended. 



